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I have hit the point of exasperation trying to get brakes bled & working on 69 el Camino, I know, not an Olds, but this is my trusted home of car forums and “A” body brakes don’t know their surname. I bought this car as a way to have a pickup bed without a truck under it. When I picked it up in DE I had been assured it was ok to drive back to CT. I got there & was told to be careful, the brakes are low. Well, I guess maybe 10-15% braking is considered “ok” in some places, I’ve driven worse having run a body shop for 30+ years and have driven cars that most couldn’t believe. Knew owner died & left a project that wasn’t quite finished, come to find out later he died in 2019! Anyway, kids knew nuthin, never saw mom, no documentation, invoices, anything.
Anyway, I get 10-15 miles away and despite virtually no brakes, the rear drums are smoking. I pull into a parking lot with an ooold school parts store and a scrap yard figuring this car is gonna be relevant to one or the other! Rear wheels so hot, couldn’t touch em, let the lug nuts fall to the ground, tripled over some gloves & rags, pulled the molten drum off & most of the hdwe fell to the ground! Put it together, checked the other side which only had a detached shoe retainer spring & made my way over a pretty cool hydro dam with a funny name and drove north through Lancaster, PA, thus staying away from interstates. Stopped at brother’s in the country outside Allentown,PA, slept over, tried bleeding the brakes in the morning aaaand no improvement. So, off towards the Tappan Zee I went, driving with the truckers in the right lane at 50-60mph, making it home alive without hurting anyone or anything.
I have been dickin around with these brakes and still can’t get them working! “New” denotes new parts that were on the car when I got it.
New front disc conversion to single piston calipers. These seem to have worked to varying extent (like 0-20%) throughout process.
New 69 style MC (bulgy sides) to new brass PV2 combo valve. Pushrod still in upper hole in pedal arm, I moved it to lower hole. Might explain the “no brakes” condition to appx 75-80% pedal travel, then a little fort application with 1* more pedal inducing a L/R lockup. New, small diameter, single diaphragm booster.
New NiCop lines, 1/4” rear supply, 3/16” to all 4 wheels, some kind of braided steel hoses front & rear. Inner diameter front & rear looked awful small (3.5mm/.086 rear vs .190 “std” hose), so I replaced with “std” hoses. Only old lines were on rear axle so I made new ones.
New rear cylinders, drums, shoes, hdwe. Pulled cyls apart, looked fine but put a kit in each one anyway. Resurfaced the drums just to start fresh and installed new shoes that have been in my attic for decades.
Fluid distribution has been inconsistent and seemingly random, at best barely acceptable and only randomly, primarily the rear has been the problem.
I replaced MC with 72 Cutlass application part. I replaced combo valve with a new PV2 I had laying around. MC fought me bench bleeding but eventually was acceptable. Fluid distribution remained as above, but always substandard, low volume. MC pushrod from booster had a huge gap(with bullet in piston), with the new MC it is now gapped at .020”, there is a small amount (~.100”) of free play inside the car with pedal at rest on upper stop.
Every step of the way has brought advances and occasional reversions, seemingly almost random, but always inconsistent.
Bleeding for the umpteenth time, I believe fronts are good but still cannot get volume out of rears and they seem to generate volumes of air that are implausible. Rear brakes are not actuating. Combo valve is pinned with spool valve stopper tool. Trying not to just keep throwing parts at it! At that, what parts are left?!? Lines are tight, no apparent leaks.
My pride and patience have been severely damaged and continue to go downhill. Any ideas would be welcomed, I’m approaching my wits end. Hoping something strikes someone looking in from the outside. “This has never happened to me before!”
Have you verified that there is fluid flow at the outlet of the combo valve? I was going to suggest bad hoses, but you've replaced those. You installed the new rear wheel cylinders? There's no chance the bleeder screws are plugged? "Bullet" in the M/C I assume means this is the deep hole M/C with the spacer that allows it to be used on the newer boosters, right? And of course a small diameter single diaphragm booster isn't going to provide much in the way of power assist, though that won't affect fluid flow when bleeding.
Thx for responding. I don’t know that this car (truck? cruck?) was even driven and only later did I figure out that it sat at least 4 years. Judging by the booster pushrod, the brakes could not ever have worked effectively.
I disassembled the rear cylinders to inspect for rust, etc, they were clean. There was some minute white “gel” for lack of a better term, talking half a tiny pinky nail clipping (or smaller) in one cyl, I think it was assembly grease of some sort, could conceivably have blocked a bleeder. Blew cyls and bleeders out, put a seal kit in each cyl just for peace of mind.
Bullet was in the 69 style MC w/ deep piston recess. Here is the gap it was “operating” on relative to the MC piston depth, it’s so far off I figured I better clarify that it wasn’t measured without the bullet spacer. From what I can gather, 020” is preferred gap. 69 MC was rusty on outside and I didn’t trust the innards so I replaced it with something known to me that I could trust.
The 72 style MC (shallow piston) had a completely different and opposite LACK of gap! Corrected adjustable rod to .020” gap and things got better but not good.
For ha has I went out and removed spool valve holder tool and put brake warning switch in just to make sure the valve didn’t move, no light so I guess it didn’t move. Started it up, stroked the pedal, stabbed the pedal just to see if anything happened. Nothing interesting going on. By feel, I would describe the pedal as not “doing” much the first third of travel, then it hits a wall and will travel no further. I perceive this as the rears not doing much and then the fronts apply correctly, not sure if that’s what’s going on but seems plausible. It’s better than thinking I got somewhere bleeding only to have the pedal travel full stroke, pretty much to the floor with little resistance.
I intend to check output from combo valve tomorrow if I can find a helper so I can watch it. This is tough as sometimes I have a helper and others I’m working alone, missing a leg & half of one side pelvis. It’s a real bitch bleeding, filling and pumping but not being able to observe more than one thing at a time. I’ve used vac bleeder (big Mighty Vac like your Vacula) and two “pedal pump” bleeders, one check ball style and the other just tube in fluid style. I MIGHT have a pressure gauge but I’m not sure on the range or variety of fittings. If it can be connected, I may collect some numbers.
I have never been involved in such a fiasco with brakes in my life! Thankfully!
My friend had a new PV71 combo valve from “The Right Stuff” (72 Cutlas disc/drum app) so we installed it. Made new 1/4” line between MC & CV as specified by “TRS” for the 72 disc/drum setup. Now getting what appears to be acceptable volume to rears but they still don’t apply!!! Fronts seem to be good. How can this be happening?!?
Contemplating having them pressure bled as there still seems to be air finding its way in to rears but I can’t imagine where.
PV71 & 1/4” line from MC got some volume to rears but still implausible amounts of air and no cylinder actuation. Third MC finally got rear brakes. Unbelievable! 2 bad MCs (1 old, 1 new) & 2 bad CVs (1 old, 1 new but old). I love old cars with mysterious backgrounds and and no documentation! At least I can safely drive it now.
