changed front pads on 99. when doing this i wound back one of the pistons. but the other would not go so i took caliper off hose and wound 2nd piston back, emptying fluid out completely. i then had to replace drivers side hose from bay to caliper. when awaiting new hose i started on pass side and removed caliper, bled it out and put in new pads and re assembled. when i put new hose on and fitted new pads i bled system and now no pedal. what do you think is the prob??? did i turn the seal in the master cylinder or empty the vacuum between the fronts. i have heard of vauxhalls having a similar prob and it takes them a while to recreate the vacuum. im leaving it till morn to retry. all advice and solutions welcome please.
brake pads changed and now no pedal
- Thread starter eamonn555
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brnocz
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power bleed it is the best easy enough to rig a system up
Irishrover
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- La Trimouille, Vienne, France
Yep-power bleed and replace all the fluid whilst you are at it. Do it in the sequence:
Rear l.h.
Rear r.h.
Front l.h.
Front r.h. (Nearest the master cylinder)
Assuming it's a RHD
Get a "Gallon" of quality DOT4 brake fluid.
Rear l.h.
Rear r.h.
Front l.h.
Front r.h. (Nearest the master cylinder)
Assuming it's a RHD
Get a "Gallon" of quality DOT4 brake fluid.
Hi I have had this with my rangie turns out that if you don't follow the procedure from the workshop manual you can get all sorts of problems. It is not just as easy as bleeding the breaks like on older vehicle.
You have to bleed the systems from the ABS Valve block and work your way through it.
You have to bleed the systems from the ABS Valve block and work your way through it.
AntS70
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When working on the braking system you must depressurise the system. If you didn't do this before you wound the piston back in you might have shagged the accumulator or pump by over pressurising it. You might get away with new seals if you is lucky if not it's a new accumulator.
Check to see if there is any fluid leaks around and under the accumulator, if there is you has buggered it!
If there are no leaks, depressurise the system before you bleed it again.
Good luck.
Check to see if there is any fluid leaks around and under the accumulator, if there is you has buggered it!
If there are no leaks, depressurise the system before you bleed it again.
Good luck.
Irishrover
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Have changed many sets of brake pads on ABS systems before and never had a problem with over pressure when retracting the pistons. Problem is, I still believe, caused by air pocket created when the hose was removed and replaced
AntS70
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You can get away with it if only changing the padsbut when i was told of one that let go, the two osf pistons were being wound back at the same time with a g cramp and small steel bar. A noticable pop came from the top end and fluid started dripping through the engine bay, to the mechanics dismay. The seal on the accumulator (or pump)had blown out of its seat. Not a nice fix.
If you can get away without doing it then all well and good, not a gamble i would fancy but each to his own and all that..
Sorry John i was referring to opening the pressurised braking system ie removing a hose or opening bleed valves etc..
If you can get away without doing it then all well and good, not a gamble i would fancy but each to his own and all that..
Sorry John i was referring to opening the pressurised braking system ie removing a hose or opening bleed valves etc..
when u say depressurise the system, how would u recommend this if u have used a tried and trusted method? as it stands i have fluid to all bleed valves but no pressure in the pedal hence i dont think the system has been re pressurised as yet. i checked around the fluid reservoir and master cylinder and there does not appear to be any leaks. thanks again.
AntS70
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With the ignition switched off, pump the brake pedal 30 times, wait 60 seconds and press a further 4 times. System should now be depressurised.
The accumulator is nitrogen charged at 80 bar and the pump creates 190 bar and increasing this with back pressure (winding pistons back) can cause seals to pop.
Page three in workshop manual brakes section.
The accumulator is nitrogen charged at 80 bar and the pump creates 190 bar and increasing this with back pressure (winding pistons back) can cause seals to pop.
Page three in workshop manual brakes section.
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AntS70
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If there are no leaks the pump has been blead incorrectly. When you turn the ignition on do you get a ticking noise coming from the pump?When bleeding the brakes you also need to bleed the abs pump, this involves switching the ignition on for four seconds then off for four seconds and waiting for the abs pump to stop running. If you dont do this you will have air contantly in the pump. It's not as simple as just bleeding the calipers and off you go, as said by others before it is a complex operation and if it doesn't work first time, you need to start from scratch and do the whole procedure again.
Download the rave cd2 and read through the braking section, you'll see what i mean.
You can get it HERE you need cd2, takes a long time to download but it's a mahoosive file.
Download the rave cd2 and read through the braking section, you'll see what i mean.
You can get it HERE you need cd2, takes a long time to download but it's a mahoosive file.
