D1 brake system question

[ESnyder]

I recently had one of the hardpipes spring a leak on my 95. i made it home, it sat for a while, and then i re-filled reservoir and limped over to a repair shop. would have some stopping power if brakes were pushed to floor, but was spraying fluid like crazy with pumping of the brakes.

Mechanic replaced line, and said he has run a ton of fluid through it and can't get brakes to power up. Says they will after a few pumps, but not initially. He thinks the master cylinder was damaged by braking without fluid somehow.

Is that possible? Any other thoughts?

Thanks!!

Enoch Snyder

 

[jafir]

Is that possible? Any other thoughts?

Sure. If the seals and other stuff inside the master have lots of wear from years of the pedal being pressed only about halfway down, and then loss of fluid cause you to be able to press the pedal all the way down, I could see you damaging the seals.

 

[discostew]

Is the pedal hard or soft ? Some porportioning valves under the master cylinder area that could be jammed in the direction of the repaired line. Try bleeding it with very light pedle pressure from all the wheels to try and move the valve to center again . Thats if the pedal is hard and you dont feel like its gonna stop . If the pedal is soft then its air in the system.

 

[apg]

Most all vehicles have a dual-circuit master cylinder setup; Rover started with the very late IIa and then the Series III to meet changes to federal motor vehicle requirements. A shuttle valve will dislocate towards the circuit that has the most fluid flow, minimizing/shutting that one down whilst still providing stopping power to the other. Now I don't have the Disco's shop manual nearby, but with the Series III, the manual advises to open a bleeder on the circuit that didn't have the issue and firmly applying the brakes to re-centralize the shuttle valve.

 

[ESnyder]

Cool, think I'll get it back and try bleeding it on the opposite corner and see if that helps.
He may have been bleeding it only from the corner he was working on.

This thread has also given me some tips on my 04, which basically will not stop when breaking at steep angles. Full pedal, firm, all i can push, and truck won't hold when under heavy load. I think i will try bleeding it from different corners to center the valves up and see if that helps.

Will check my shop manual for D1 as well.

Thanks!

ES

 

[edthediscoman]

04 wont stop due to ABS.

The D1, get rid of the ABS fuse, then diagnose. I just did all my brake system. from Master to rebuild of calipers. I Pulled the abs fuse (due to a really steep brake issue - I decided non was better than death) and it helps to diagnose it in hard core manual foot brake mode.

 

[ESnyder]

I took the ABS module out a long time ago... It's a worthless invention IMHO. Dash light bulb followed quickly after that!


Mechanic had bled them pretty well, working his way around the truck. We're putting on a master cylinder now and we'll see what's up.

 

[ESnyder]

follow up:


on the 04 i don't feel any pulsing, is it still the ABS? also, I guess the ABS stays on in low range? some trucks i've had turn off the ABS in low range, cruisers especially. for the 04 i guess it has to stay active because that is what runs the traction control. Not really crazy about the system so far. seems to be a little better than open diffs, but not as good as a detroit or arb in the rear. the braking is a real problem, will have to keep the e-brake adjusted well and use it occasionally, because at really steep angles the stock brakes aren't doing it.

Any specific pads do better? almost feels like these are glazed over or something.

ES