Matt's 1970 Opel GT - Project Log

Back on the transmission...

Last time I disassembled one of these shafts, it took me hours of jigging and hammering to finally get it to give up. So this time I tried a cheap bearing puller I already had. Wasn't strong enough. I left penetrating oil and pressure on it overnight to see if it'd loosen, but, no luck.


So, I did what worked last time, I cut some angle iron to brace the gear, and got ready to hammer on it. But before I did, I just closed the vice enough to loosely shoulder the gears, and a few bops with the hammer the gears drove right off each side. Took less than a minute. First time in a long time something's gone faster than I thought.


Looking inside the tail shaft, the bearing that supports the prop shaft is really badly chewed up here. I presume the diagonal groove is for oil, but the other gouges would ruin whatever they were connected to. Luckily I have a smooth one from my other tail shaft, I presume I can press (socket + hammer) it out and replace it. Makes me feel less bad about destroying a not-perfectly-good transmission:


Next job is to thin the shaft down to something I can fit in the coupler. Since I won't have the benefit of it spinning on the motor until after I'm done, Had to think of some other way of thinning it out. I built up a quick cradle for it, supported on each end with a tapered bolt (the shaft already has conical indentations on centers). I'm going to ziptie a drill down to the base and connect the two with rubber bands or hair elastics or something as a drive belt. I won't be machining it, it's steel so I'll just be using the grinder, so, it doesn't need a lot of speed or strength:


I haven't decided which diameter to use. The left 50% of the shaft is 25mm. Maybe that's a good target. It's also very close to 1", and I have a 1" drill bit to bore the coupler out to. Larger is better (more grip), but I don't know how strong my home-cast coupler is and I want to leave at least 1/4" of wall thickness on it. I wonder if I should do some friction calculations based on the motor torque torque. I could also try filing a keyway, but, taper-lock should be sufficient. Anyone has better ideas I'm all ears.

Pausing on that a bit to mull it over.


Back to brakes!

Dug up my old brake calipers I won't be using. But with J-tubes I rescued:


At some point in the past I must have bought 2 different brake flare tools, and a tubing bender. All were unusable garbage. I practised at least a half-dozen times and couldn't get useful flares out of them. This is also great practice for later, to develop a habit of using a tubing cutter to using the flaring tool without the middle step of sliding the tube nut on before you flare the tube and make it impossible to add later. There's no way that won't have consequences. I called up all the usual tool loan places, none had brake flare kits. If you want to murder your whole family, just try to learn how to do your own brake flares with a crappy tool and the rest will take care of itself.


So, I had to spend $60 to buy one, that still sucked, and still didn't give me great flares. It's a poor chef who blames his ingredients, but, can't turn chicken shit into chicken salad:


I decided to try to re-use my (intact) original front brake lines, but since I'm T-splitting the front (CRV MC doesn't have dual ports for the front), I'm mounting the T-splitter on the radiator wall, and trimming the brake lines to fit. I can't re-use the existing tube nuts anyway, because they have such a large shoulder before the threads, and my M12-M10 adapters have such shallow receiving threads that they were only mating by about 1/2 a turn!


Bit of a goofy brake line path. First, the front brake port on the MC is pointed like 30 degrees upward!? Had to do some pretty sharp curls on them to get them to clear the hood hinges. Goofy questionmark shaped ends:


Likewise with the T-splitter. Tried to find a place out of the way for it, ended up making a rollercoaster to get the lines there and still have some flexibility to insert them. Loop-dee-loops everywhere:


Among the most frustrating parts of the build so far. Took 20 attempts at bending each line, just for the last few inches. Oh, and, I definitely don't recommend bending your brake lines first, and then looking up how to flare them after. Because sharp bends near the end + flaring tool = you can't slide the tube nut back far enough. So I had to unbend the last two inches, flare, then re-bend a now work-hardened tube. Again, if you want to murder your whole family, try bending your own brake lines for the first time and the rest will take care of itself.

Oh and by the way, you only get 1 chance to flare it properly or you're throwing it away and starting over.

Cont'd.

Cont'd

Rear line wasn't too complicated. Made it from scratch since my old line was cut off by the previous owner when they took out the trans tunnel. I cleaned up a an old flex-hose (we'll see if it holds), and, just barely remembered in time to slide the 5 rubber isolators and flare nut on before flaring. Whew. That is my last brake line. That means I dodged the bullet of forgetting to put a tube nut on.


Just have to add flex hoses and J-tubes to the front brakes and I'm ready to pressure test.

...

That was too easy. I'm forgetting something. What did I miss?

...

Oh yeah, the whole residual valve thing I soldered for the rear line. It's still at a friend's house where it fell out:



... damnit. Now I have to cut up the rear line to insert it. After all the pain in the ass of doing the rear line in one long continuous segment, I'm cutting it in half anyway.

Lots of room to still forget a tube nut and screw up a flare (none of my flares are particularly good, I dunno how I feel about using them).

One thing that didn't cross my mind until I was done... how to bleed these? I have all these stupid loop-dee-loops, my line heads UPWARDS from the MC (by factory, but, not having room to clear the hood hinge to steer down without going up and back first makes it worse).

I think it's 50/50 whether I end up keeping this, or throwing it all away and starting over.

Oh, and let's add it up:

• $25 brake line
• $15 tube nuts
• $60 flare tool (if I don't return it, not even counting the other 2).
• Let's not count the $15 for more tube nuts since I lost my first pack.

... $100. Murdered my whole family twice. Still ended up with a shitty result.

How much does Opel GT Source sell a pre-flared brake line set for? $63, and sometimes on sale.



The false economy of saving money by doing it yourself.

If I wasn't using a different brake booster with an added T-splitter, this is definitely one of those "just pay someone to do it" things.

How's that to-do list coming?:

• Find somewhere to mount the residual valve for the rear lines and mount it. -OOPS
• Find somewhere to mount the T-splitter for the front lines and mount it.
• Make new front or rear brake lines, if you want to.
• Make the central brake line that goes to the diff.
• Actually put the brakes onto the wheels.
• Find a larger reservoir to connect the mini-reservoir to, and mount it.
• Decide if you want to swap the whole rear end for the (better, more modern) spare rear, after cleaning it up, now, or later.
• Fill with fluid, bleed.
• Figure out how drum brakes supposedly work and hate your life adjusting them.
• Test brakes manually.
• Connect up all wires, fuses, and see if the iBooster actually works or whether it's a dud.

remy_martian said:

On the shaft - take it to a machine shop. Your Egyptian lathe setup is not going to cut it for concentricity and it'll vibrate itself to death from imbalance. Same goes for a coupler.

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Coupler was fine at 100hz (though, that's 100hz to the OpenInverter algorithm, which, apparently might only be 33hz since mine's a 3 pole pair motor?). Still, that's half way there. No noticeable vibration. The tailshaft I have lower hopes for, but I'm going to try it out first. I'll probably throw a dial indicator on it at some point and see how bad the runout is. I'll need to do that anyways when I figure out how I'm going to be mounting the tailshaft housing to the motor.

If I was going to take it to a machine shop I'd just throw it in the 8hp Challenger lathe and do it myself. In the spirit of a homebrew budget build, I'm at least trying to avoid using beyond-household tools or "just pay someone to do it" kind of things. Average households curious about converting an EV don't have access to a Tormach CNC mill, or 8 foot long 4000lb metal lathes, or 4 kinds of welders or waterjet cutteres. And if every solution is "And then pay someone to make this for you, and then pay someone to make that for you", then the build is just a shopping kart. That said, if it doesn't work it doesn't work and I'll throw in the towel and chuck it up in the lathe. Likewise I'm not building my own motor from scratch, or prospecting my own minerals, so, there has to be a limit somewhere. I'm just happy to push it a bit more than most people would. I managed to do bodywork with a flux-core welder and have half of it turn out good enough, which everyone said was impossible to do. Just took some patience.

You'll be running the motor at around 4krpm, not the hundred or two where your methods might work.

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I kinda figured that, but then turning that coupler on the motor surprised the hell out of me with how well it turned out. I think it's just fine, but, I don't think I have a hope of the tail shaft being within an order of magnitude as precise.

I'd also do a hardness test on the shaft before anything. It may be case hardened.

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I presume it's case hardened. Doesn't really matter to an abrasive wheel, it's not harder than aluminum oxide, sparks will fly just the same.

remy_martian said:

Breaking the case hardening along the shaft may snap it at the discontinuity under load. I'll defer to the MEs here on that one.

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Never crossed my mind. I'll bug some of my ME friends.

I suppose I could murder the heat treatment on the shaft via heat, but, my thoughts are that it's probably not a problem, it's not the weak link.

As far as DIY, you should DISCOURAGE people from skimping on the important stuff. People build their own engines all the time, but nobody does their own line bore or crank grinds. The coupler is one of the most critical mechanical parts of a build.

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Well, like the tail shaft, the coupler isn't going to be a safety issue (any more than losing power at speed would be). If it breaks, it breaks. It'll be enclosed in the tail housing and coupler housing.

Making your own coupler has been a staple of DIY EVs for a long time.

Your Flintstones build methods are, if anything, entertaining.

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Likewise, I'm enjoying myself. I don't mind playing around and finding out what works and what doesn't. If everyone obeyed best practices, the solution would just be "Buy an EV".

Duncan said:

If you are sensible and use the copper nickel brake lines just about any flaring tool can do a good job

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I totally underestimated the frustration and challenge of both bending and flaring brake lines. I don't regret getting steel lines in terms of bending, it was bad but manageable, but, flaring, yeah. Brake lines were one of the first things I bought, without really knowing anything at all. I even bought tube nuts without knowing there were different kinds of flares.

...

Finishing the brakes, got the J-tubes and really junky rubber flex tubes on. I'm skeptical they hold pressure. New ones are about $20 apiece.


So, now other than having to cut the lines to insert the residual valve, the system is temporarily consistent. I was tempted to fill with fluid, bleed, and pressure test them tonight but, it'd just make a mess when I cut them in a couple days.

And, my high precision machining test for the night:


I'm reasonably pleased with the result. We'll see how fast I churn through rubber bands. Wrapped a couple folded pieces of electrical tape on the shaft to give it dome so the bands would stop walking. Just about deafening to listen to.

The grinding wheel hardly removed any material, I kept it on the 3/16" wide ridge, and barely scratched it. Maybe because the grinding disc is full of melted zinc still. But it lasted 5 minutes and was good enough of a test to try longer later.

Holy sh!t it maybe worked!

Watch as my flap disc slowly digests the left half of the tailshaft and transforms it into shop glitter over a period of 3 hours:


I probably pulled a pound off the weight.

Drill and grinder got uncomfortably warm (especially the 90-degree gearbox in the grinder head) after about 5 heavy minutes, so I took breaks about that often to spray water into their air vents while they ran. Cooled them (and me, with the spray) right down to ambient in a few seconds. Wouldn't ever do that unless I knew I was going to be running them for a long time to let the air and heat dry them out. Don't seem to be any worse for wear.

Look at those starbursts. Definitely case hardened (the harder the steel, the more the sparks explode into starbursts after a bit):


Never switched to an actual grinding wheel, and, couldn't really bog down on the shaft as it was only spinning with the power of a couple rubber bands (which lasted the whole 3 hours, in a spark stream at that). But for 3 hours it was a steady sheet of sparks like that.

Turned out decent in the end. I stopped when some sections hit 1.005", but some were still as high as 1.015". Flap disc makes it kinda hard to tell where it's cutting, and I wanted to err on too big until I see how much my 1" hole cut into the coupler gets wallowed out by my drilling attempt. Maybe even 1.015" was too ambitious. If not, when I get a measurement, I'll even out the high spots down consistently. The bearing rides on the 25mm part of the shaft, which is only 0.015" below 1", and despite wrapping that section with tape, I'm rightly paranoid about even nicking it there. The bigger deal isn't diameter, it's eccentricity, and, proof of the pudding will be in the eating, but, I think I'm quite happy with it.


...

Toggling back to brakes, I got my brake coupler back, and decided to weld a thicker shoulder onto it for the crush washer to press against. I just welded a band around it, and then chopped it in the middle of that band. It's ugly but seems like it'll work.

Then I chose a place in the engine bay to mount it, and cut the rear brake line there to accommodate. One last use for my brake line flare kit and the brakes will be done...


... M##### F#####...

The die on the right should look like the die on the left. But the centering pin on the die broke off inside the tube. Didn't last 15 f'ckin' flares. I tried cutting it off and doing without, but, it (unsurprisingly) parallelegrammed to the side like a soggy, forgotten cheesecake.

There's probably not enough room to mount it where I want to mount it anymore (this'll be trim #3 on that line), and, I really wanted to say "Brakes Are Done!" tonight.

Whelp... isn't the end of the world, I suppose it's time to borrow a friend's (probably better?) brake flare tool, and maybe even remake the brake tube itself.

More brake work:

- Recovered my soldered brake coupler.

- Stopped by another GT owner's to exchange useless parts for useful ones. Snagged a couple crush washers, some better J-tubes, and some advice.

- Had a good look at an assembled GT and where the pushrod and cable goes, mostly reassuring me that my master cylinder and reservoir are not going to be in its way.

- Since the brake coupler was a coupling nut that I drilled out and re-threaded, the walls are pretty thin and don't provide much of a face to crush against. So I gingery welded a flange onto it one tack at a time without setting off the smoke alarm. Then cut it in the middle of that flange and trimmed up the edges. It's hideous but better than it was.


- Used friend's flare kit (same as mine but worked better) to flare the ruined line, flared the rear line, crushed the crush washer and put it all together. Brake lines complete! I put away all my brake flaring stuff nicely, thus ensuring it will have to come right back out again soon.


- Bench bled the master cylinder as pointed out by @gregski . Which is apparently a thing you need to do, otherwise air can get somewhat permanently trapped? Anyway, had some spare vinyl hose and did that:


- Reconnected the brake lines, used the tube and funnel as a secondary tank, and started bleeding from the rear right. Got nothing out. I didn't even so much as brush the dirt off this axle before I installed it, let alone clean out the lines, actuate the cylinders, etc, so this isn't a big surprise. The GT it came out of was rusted right through. I have a second (newer) axle I'll clean up, but this wasn't that. Figured maybe there's so much air in the lines the fluid has no pressure to blast through the crud, so I moved to the rear left instead. Maybe got a few drops out, not much.

Moved onto the fronts, got fluid through those. Lots of fluid. Hmm, I can hear much more fluid than I'm seeing. And now there's a puddle of brake fluid on the floor. Front-right fitting failed at the T-splitter. No amount of tightening fixes it. Who flared this damned thing?

Ugh, well, maybe reflare that line, maybe re-make that whole line, and then start the bleeding process all over again. But it's 5am, and in the wise words of Jesse Ventura...


Not there yet but progress is being stubbornly bludgeoned forward.

Um...this is an automotive braking system
...& NOT really something to be played with

1.) How much homemade stuff will the USDOT let you "rig up" on the brake system of a passenger car?

2.) How much do you (or should you) trust all of those "rigged up" connections, on your braking system
...if/when a little 'ol lady pulls out in front of you at 45MPH?
...will they "hold" when you really need them?

I'm all for DIY'ing stuff
...but, "man has got to know his limitations" (Swetting Bullets, Dave Mustane)
...& do you really think it's a good idea to put your life (& possibly others) on the line, by DIY'ing (rigging up) the brake system on your car?
...or being a leader, by showing others that any of this, is a good idea?

I understand the need for cross-using components
...but, welding brake couplers together
...&...well...I'll just leave it at that

Functional Artist said:

1.) How much homemade stuff will the USDOT let you "rig up" on the brake system of a passenger car?

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About as much as the Martian Department of Transportation would in Canada.

No inspections in my neck of the woods.

Lots of people restoring classic cars are making their own brake lines. That's why they sell replacement brake line and brake flare tools in every auto parts store.

2.) How much do you (or should you) trust all of those "rigged up" connections, on your braking system

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- My braking pushrod coupler is an INCH thick. The OEM one it butts up against is less than half that, so less than 1/4 the cross sectional area. The bracket that holds the brake pedal on the CRV's iBooster in OEM configuration is not even 1/8" thick steel. It's fine. It's cosmetically crooked, but it's not a rotating shaft, it's a pushrod, aligned on center. It's ugly but irrelevant.

- The brake line coupler I made is probably 300% as thick as brake line. The silver solder isn't mechanical, it's only a seal, and is sealed from both sides and maybe everything in between. The mechanical connection is about 3/4" of threaded connection, when the factory connection is like 1/4". I bet it's 1-2 orders of magnitude stronger than a flare fitting.

- My brake flares are the worst part of the system, and they're the thing I'm doing with the correct tools and methods.

So, how much should I trust them? I dunno, as much as anyone who's ever made a brake line or trusted some shop monkey to make them.

...& do you really think it's a good idea to put your life (& possibly others) on the line, by DIY'ing (rigging up) the brake system on your car?

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If I was cutting corners, taking a factory 1/4" rod and saying "Oh, 1/8" thick is probably strong enough", then perhaps I'd be worried. But I'm not, I'm going in the other direction.

IF there's a failure on the lines, it'll only fail front or rears, and I have 2 redundant breaking systems (regenerative and cable-actuated hand brake).

Really, the flares are the only thing I think is kinda shitty, and I'm obviously testing them.

You can fearmonger about anything... Do you really trust changing your tires yourself? What happens if your tire comes off on the highway and you lose control and kill someone, and the tire causes a bus full of kids to fall off a bridge?

It's not going to be a problem until there's a problem.

Here's hoping there isn't one and that the eBrake works better than the shitty one cars had in the 1960's and 1970's.

The flared lines are not my concern, really.

It's the silver solder and the unknown corrosive effects of brake fluid on silver, for example, as are the high pressures I expressed concerns about earlier. I don't know of any construction, industrial, or farm equipment hydraulics that use solder as a threadseal. You're in uncharted territory here.

I also am a bit concerned about the actuator - it won't be a problem unless the booster (or its power circuit/motor) fails and you drop from warp to impulse drive (unboosted emergency stop). Untested.

Warrants nondestructive testing to maybe a safety factor of 3-5 (guessing) on pedal force in my book. I personally think yours is better than Gregski's cobble-up, but that's just opinion vs analysis and engineering approval of what you've done. Duncan is the Mech Eng in this conversation, so he's the resident expert if there is one.

I'd NDT the brake pedal forces once the system has its full complement of baling wire and duct tape. I'm thinking 3-5x top of my head on max foreseen pedal force (using a hydraulic ram cuz you ain't getting a Sumo Wrestler into that dinky little car).

Your build, your choices, just that safety items like brakes and steering cannot be subject to the Dunning-Kruger effect and I think you should listen to what Duncan has to say on this because of the DKe you have justifying what you did.

It's not a problem until there's an incident. An incident for which you may not be at fault, but the drama of a lawyer painting a picture of the brakes to a jury may make it your fault. The law is based on emotion, not logic.

nuff said, carry on as needed,

🍿🥤

Duncan said:

There is no way that I would TRY and use one of them on a steel brake line - THAT needs the proper (very expensive) hydraulic flaring tools

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Tool specifically says it's for soft steel brake lines.

I called a dozen or so places today asking if I brought in a brake line, if they offer the service of flaring them.

Almost everyone said the same things:

• No one does that anymore.
• I've been here X years and no one's asked.
• We used to have a tool that does that but it was lost/broken and no one's bothered to replace it.

Midas said "If it's just a few, buy me a coffee or a lunch and I'll do it on my break for free."

There's 3 tiers of brake flaring tools:

• The stupid wingnut ones I have ($30-$60)
• The "deluxe" ones with a revolver and a long lever. ($500)
• The big hydraulic ones ($2000).

I was hoping they'd have the deluxe one, because it's so fast, even paying shop rates I bet I'd get it down to $5/line including setup and teardown time. It's literally 10 seconds per flare.

I might still just replace them all with Cupranil lines. I wasn't really clued into anything about brakes when I first bought them and figured steel would be better. That can wait until after some testing. The entire rear axle is temporary and to be swapped out for my nicer axle that I'll take time to clean up. The rear brake cylinders on the one that's on there now almost certainly don't work, I have rebuilt ones that'll go on the new axle.

...

remy_martian said:

It's not going to be a problem until there's a problem.

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Yeah, that's the troubling thing, there's not a graceful way to test it.

It's the silver solder and the unknown corrosive effects of brake fluid on silver, for example, as are the high pressures I expressed concerns about earlier. I don't know of any construction, industrial, or farm equipment hydraulics that use solder as a threadseal. You're in uncharted territory here.

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It'd only affect rear brakes, which have regen and cable, and are only 10% of my stopping power anyways.

This video from a manufacturer demonstrates how to repair a damaged brake line with their silver solder. It's not the same stuff I used, I used cheap lead-free "silver" plumbing solder with presumably a small percentage of silver.

Another source says brake fluid does not corrode metals. Only the moisture that absorbs into it corrodes metals.

So, that mostly reassures me.

I also am a bit concerned about the actuator - it won't be a problem unless the booster (or its power circuit/motor) fails and you drop from warp to impulse drive (unboosted emergency stop). Untested.

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Well, that janky pushrod is how it's done OEM. Only my coupler is significantly thicker than the OEM one.

Duncan is the Mech Eng in this conversation, so he's the resident expert if there is one. I think you should listen to what Duncan has to say on this because of the DKe you have justifying what you did

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F'ckin' Duncan has repeatedly tried to convince me to not even have a brake booster, because it's unnecessary on a car this size.

Y'all can't keep a consistent level of paranoia.

remy_martian said:

^^ needs a "double flare", not a single, to do it right.

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Yes, of course. Single flare would be easy. It's the bubble portion that's a bit wonky.

Also, my brake lines aren't the cheapest ones. They're plastic-coated steel. But part of what makes them look so awful when flaring is that the plastic coating crumbles/rips off when you crush the tube to flare it, (also making it slippery and wanting to slide away unless you really crank it down).