I have a b"brake issue" on my '88 SS. One of the suggested solutions is to adjust the length on the pushrod between the pedal and master cylinder. Is this possible on a late G-body? Any suggestions?
Brake issue...
- Thread starter TorK
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As I recall, the push rod isn't adjustable on most G-bodies.
There's a go/no-go gage that Kent Moore has that is used to check the push rod length. If it fits, it ships sort of thing. It's a little flat plate gage with notches in it to check the push rod. The remedy for an out of spec rod is, if it fails the gage check, the tech was supposed to use a service part push rod which was adjustable to get it in spec. I don't know what the actual measurement is supposed to be, though. I've never found anything in the CSM about the inches or mm settings. Just the go/no-go gage.
The adjustable pin is GM p/n 18060010 with JM5 (Delco) typical dual-diaphragm (thicker booster) G-body brake boosters. The JM7 single diaphragm (thinner booster) early G-body boosters apparently can use the same adjustable pin part number as far as the parts book goes.
There's a go/no-go gage that Kent Moore has that is used to check the push rod length. If it fits, it ships sort of thing. It's a little flat plate gage with notches in it to check the push rod. The remedy for an out of spec rod is, if it fails the gage check, the tech was supposed to use a service part push rod which was adjustable to get it in spec. I don't know what the actual measurement is supposed to be, though. I've never found anything in the CSM about the inches or mm settings. Just the go/no-go gage.
The adjustable pin is GM p/n 18060010 with JM5 (Delco) typical dual-diaphragm (thicker booster) G-body brake boosters. The JM7 single diaphragm (thinner booster) early G-body boosters apparently can use the same adjustable pin part number as far as the parts book goes.
A local mechanic suggested it a possible solution.. I have trouble with the brakes, I changed the brake fluid, after that my brakes feels "spongy", like there is air in the system. I have tried different ways to bleed; The "ordinary way" with one guy inside car, pumping, vacuum bleeding at each wheel, "gravity bleeding" with opening bleeder valves an letting fluid run "by itself", and pressurized bleeding with air pressure in the reservoir... I have changed all the rubber hoses, and fit a new master cylinder.
I have bled the brakes on the car before, as I have changed rear wheel cylinders and front brake hoses a few years ago, no problems!
I have worked on my own cars for over 50 years, but now I am stuck with my problem... And yes, I use new brake fluid, as described in my shop manual.
And my brakes was working perfectly before I changed the fluid..
Instead of adjusting the rod as suggested I tried putting washers between power booster and master cylinder instead of adjusting the rod "shorter". No change..
My next attemt for "adjustment" will be putting a "shim" between rod and master cylinder piston, to try a "longer" rod. Iwill try this tomorrow, now I have a few beers that need my attention...
Any other suggestions?
I don't think you need to make any adjustments anywhere, sounds like it just needs to be bled.
I installed the disc/disc valve on my SS, bled the front the normal way with someone pushing on the pedal pretty firm. Did the back one gravity first and then moved the pedal very slowly given the little piece in the combo valve that slides. Basically slow enough to push fluid out until there was no air.
The design of it is with normal push of the brakes that slider will move in there to block off any part of the system that loses pressure suddenly. The conventional way we all know how to bleed any corner is a pretty firm push on the pedal to move the fluid out of the open bleeder on each corner. Close bleeder, build up pressure, repeat process. That release of pressure will move that slider in the valve.
My thought was to go slow just to move the fluid until the air was gone. Basically open the valve and slowly push the pedal to the bottom, close bleeder, pedal back up and again a single slow push with the bleeder open. Didn't give it any pushes on the rear system to build up any pressure. It worked and all 4 corners on my car work very well.
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