Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[tango]

i had a similar problem on my car turned out brake servo was knackered

[madhatter1960]

Yes, calipers were removed from car, then bleed nipples removed, then pistons slowly pushed back..  They were spongy even before i did all this.  I thoiught it may have made them better, but they still feel the same.

Thanks for any help..

[madhatter1960]

Noel, sorry for my earlier remark.  I am just at the end of my tether with them.

[Kevin Wood]

Were the bleed nipples opened when winding the pistons back into the calipers?

Could be that a seal in the master cylinder has inverted.

Although this is often quoted IMHO I think there's more urban myth to this that fact! Brakes have been bled in their millions over the years without bleed nipples being opened before pushing caliper pistons back.


My brakes were bled & bled & always felt spring, rather than spongy, but were put back to 'normal' after new discs were fitted. Inboard sides of discs wee both fubar'd 

Perhaps so, but it's still good practice IMHO because it discards the old fluid that has been sitting in the "hot" end of the system deteriorating. 


Regarding air in the ABS modulator, I would only expect this if the system had been practically drained of fluid.

EDIT: Then again, you say the calipers were removed. Were the brake lines left open while they were off the car?

Will the pedal gradually creep down to the floor if held down, or is it just spongy with no "creep"?

Servo can be checked easily. Switch off engine and pump the pedal a few times, After 4 or 5 pumps of the pedal it should get significantly harder.

Restart the engine with pressure applied to the pedal and the pedal should sink slightly.

[Michael2.6]

I had something like this on my miggy

turn out to be the brake servo unit.

[noel]

Noel, sorry for my earlier remark.  I am just at the end of my tether with them.

it may have sounded a thick question but it has been known for people not to bleed them after fitting new discs & pads.
was not trying to make you sound thick & i understand your concerns

[hotel21]

As KW says earlier in the thread.

If calipers were removed and flexi's left unclamped then fluid could easily have wept ot and air went into the lines and up into the ABS accumulator.

If that is the case then the brakes need bled with a tech2 (VX computer) attached so that the ABS unit can be operated remotely ('excercised') ensuring all potential air is removed.

PS - this is really quite a friendly forum with LOTS of good advice, freely available, with good banter.  But some of the older farts do not respond well to DER type comments such as posted earlier.

Just saying like....      

[noel]

As KW says earlier in the thread.

If calipers were removed and flexi's left unclamped then fluid could easily have wept ot and air went into the lines and up into the ABS accumulator.

If that is the case then the brakes need bled with a tech2 (VX computer) attached so that the ABS unit can be operated remotely ('excercised') ensuring all potential air is removed.

PS - this is really quite a friendly forum with LOTS of good advice, freely available, with good banter.  But some of the older farts do not respond well to DER type comments such as posted earlier.

Just saying like....      

thanks and yes i am old school

[petec]

This thread is pretty old now so presume issues have been resolved but I have a similar problem on an 03 2.6 estate and wonder what the final cause was rather than starting a new thread. I notice that your brakes seemed soggy despite repeated bleedings, this may be different to mine as my pedal sinks slowly over halfway over about 30 secs and stopping power is not impressive, when bled pedal is firm and car stops fine. no external leaks anywhere so suspect air being drawn in somewhere. the same symptoms in my old 97 vectra diesel were caused by the master cylinder and to honest I had assumed this would be the problem but several people have mentioned ABS modulator as a possible cause.

Madhatter1960, did you resolve your problem and what was the cause?
thanks

[Webby the Bear]

As KW says earlier in the thread.

If calipers were removed and flexi's left unclamped then fluid could easily have wept ot and air went into the lines and up into the ABS accumulator.

If that is the case then the brakes need bled with a tech2 (VX computer) attached so that the ABS unit can be operated remotely ('excercised') ensuring all potential air is removed.

PS - this is really quite a friendly forum with LOTS of good advice, freely available, with good banter.  But some of the older farts do not respond well to DER type comments such as posted earlier.Just saying like....      

and the younger farts! plain rude if you ask me 

[petec]

no offence intended and sorry to appear to hijack this thread but just wondered whether there was a final resolution to the brake problem

[Webby the Bear]

no offence intended and sorry to appear to hijack this thread but just wondered whether there was a final resolution to the brake problem

we were talking to the OP mate 

[Kevin Wood]

A pedal that sinks gradually under a little pressure is indicative of a failed cylinder seal or a leak in the system, IMHO.

First off, press the pedal firmly for a minute or 2, then have a quick look around the whole system for any evidence of a leak. Trace the system from master cylinder to the ABS block then down to each caliper, looking for any signs of a fluid leak.

If there's somewhere air can be drawn in, fluid will leak too.

If there's nothing to be found there, it might well be a failed master cylinder seal.

Omegas do tend to have a little more pedal travel than some cars IME.

With any brake problem, if the fluid isn't known to have been replaced within the last 2 years, that's top of the list.

[dbug]

As KW says earlier in the thread.

If calipers were removed and flexi's left unclamped then fluid could easily have wept ot and air went into the lines and up into the ABS accumulator.

If that is the case then the brakes need bled with a tech2 (VX computer) attached so that the ABS unit can be operated remotely ('excercised') ensuring all potential air is removed.

PS - this is really quite a friendly forum with LOTS of good advice, freely available, with good banter.  But some of the older farts do not respond well to DER type comments such as posted earlier.

Just saying like....      

Hey less of the old 

[petec]

I think I definitely qualify as old, my first car had cable brakes and side valve engine.

Thanks for your thoughts Kevin, I changed my fluid 2 months ago as it was spongy and the pedal firmed up nicely, no sign of any leaks anywhere so was thinking along the lines of master cylinder seals beginning to fail.  Pedal travel increased over about 4 weeks but if pumped once its much firmer and higher so guessing a little air might have been drawn in at the rear master cylinder seal. I will take it out this weekend and probably replace it.  On same issue there are lots of replacement seal kits on fleabay, has anyone used them? , if the bores are not worn it would be cheaper than a new master cylinder.