Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: madhatter1960 on 01 March 2012, 21:23:33
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Hi, i have replaced discs & pads all round, also all brake pipes including the flexi's. My brakes still feel spongy, if i keep my foot on the pedal it goes down, not all the way, but it doesn't feel right. Does anyone have any ideas as to what migh be causing this?? Could it be the master cylinder, or the ABS pump??
Kind regards
Paul
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have you bled the air out of the system :-\
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DER, of course they were bled, new fluid as well. Bled them 3 times all round. Still no better..
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DER, of course they were bled, new fluid as well. Bled them 3 times all round. Still no better..
and was the ABS modulator 'exercised' during the bleeding process? ::)
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Modulator exercised?? Please shed some light for me..
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Probably air in abs mod - needs TechII to exercise modulator to shift whilst bleeding. ;)
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What is TECH11???
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What is TECH11???
DER! ::) ::) ::) It's what Vauxhall use to 'talk' to your car with :y :y
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What is TECH11???
DER! ::) ::) ::) It's what Vauxhall use to 'talk' to your car with :y :y
Oh dear :o
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Were the bleed nipples opened when winding the pistons back into the calipers?
Could be that a seal in the master cylinder has inverted.
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What is TECH11???
DER! ::) ::) ::) It's what Vauxhall use to 'talk' to your car with :y :y
Oh dear :o
DER, of course they were bled, new fluid as well. Bled them 3 times all round. Still no better..
I was only replying in a similar vein ....... ;) ;) ;) :y
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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 ;)
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What is TECH11???
DER! ::) ::) ::) It's what Vauxhall use to 'talk' to your car with :y :y
Oh dear :o
DER, of course they were bled, new fluid as well. Bled them 3 times all round. Still no better..
I was only replying in a similar vein ....... ;) ;) ;) :y
Yep realised that mate - just "commenting" on ops comment coupled with his lack of knowledge - DER liked your response :y
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What is TECH11???
DER! ::) ::) ::) It's what Vauxhall use to 'talk' to your car with :y :y
Oh dear :o
DER, of course they were bled, new fluid as well. Bled them 3 times all round. Still no better..
I was only replying in a similar vein ....... ;) ;) ;) :y
Yep realised that mate - just "commenting" on ops comment coupled with his lack of knowledge - DER liked your response :y
;) ;) :y :y
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DER, of course they were bled, new fluid as well. Bled them 3 times all round. Still no better..
it was a straight forward question wish i had'nt of bothered
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i had a similar problem on my car turned out brake servo was knackered
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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..
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Noel, sorry for my earlier remark. I am just at the end of my tether with them.
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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.
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I had something like this on my miggy
turn out to be the brake servo unit.
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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 :y
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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.... ;) :y
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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.... ;) :y
thanks and yes i am old school ;D ;D :y
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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
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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.... ;) :y
and the younger farts! plain rude if you ask me >:(
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no offence intended and sorry to appear to hijack this thread but just wondered whether there was a final resolution to the brake problem
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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 :y
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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.
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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.... ;) :y
Hey less of the old :o :) :) ;)
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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.
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Yep, if you can get a set of just the MC seals then that'd be worth a try, for the relatively small outlay.
You might well need the ABS ECU exercised using a Tech 2 when bleeding it after a MC change, though. I would bleed a little fluid through by loosening each of the outlets on the master cylinder one at a time to try to minimise the risk of this before bleeding the system, normally. This will minimise the amount of air that will get fed through the ABS ECU.
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Tanx, sounds like a plan! :). I will try and seals before the weekend and have a go. I don't have access to a tech2 and hopefully will get away without needing one but air does get into ABS unit is it possible to flush it through with a pressure bleeder (easybleed) or will airlocks remain in ABS.
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Have you tried the brake servo unit
this also makes the brake pedal go to the floor
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don't think its the servo because if I bleed the brakes everything is fine for a week or so then the pedal starts to feel progressively soggy.
IMO it feels like air getting into the system and barring leaky pipes/connectors I think it could only get in through master cylinder seals or caliper seals. The calipers are all dry but have not taken the MC off to see if there is any seepage from the end so think this is the next most likely cause (hopefully).
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I would say msater cylinder is failing,had the samething on my old astra van,,it would be fine for a week or two,then go soft or straight to the floor..
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well, put new master cylinder in last weekend, sods law that mine is a slightly unusual one and therefore more expensive. Took front calipers off, cleaned and painted them (hate working on rusty gungy brakes) and replaced front pads at same time.
I bench bled the cylinder and had no problem with air getting trapped in Abs unit which some folk had warned about. With engine off, pedal is now firm, near the top and does not sink, with engine running pedal is firmer and again does not sink, after few miles brakes are MUCH better than they have been for ages although it was good enough to pass an MOT before.
Brake sensor is an absolute pain, only one on my late facelift but very difficult to remove it from old pad without breaking it. I did manage to salvage sensor this time but will get new one next time I change pads ;)
Next week its change the broken rear spring time...sigh
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Well done mate. good diagnosis work from everyone.
these sensors, where do they attach from and to? the ones on my old banger have been cut and taped up so i cant see where they go.
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Pic of sensor
(http://88.191.108.165//images/BMP062/FWI243.BMP.JPG)
Connector is the black one just to right of droplink arm
(http://images.omegaowners.com/images/faq/miscpics/frontsuspensionpic.jpg)
Sensor "pip" pushes into hole near clip at top of pad
(http://t0.gstatic.com/images?q=tbn:ANd9GcS8wnTN97pv0if04ogqye9Tx87gNy5uH3Z9lJh3gwKqA4ZUHxLq)
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One prefacelifts and apparently early facelifts there are wear sensors on both front wheels, on my 2003 there is only one on the nearside front.
The wear sensor has an L shaped plastic? fitting on one end, about 1/2metre of lead and a 2 pin connector on the other. The connector it goes into is clipped vertically on the inner wing right behind the strut as you look at it through the wheelarch, about halfway up, its the black connector.
If your motor has HID lights the level sensor will be just to the right of it (its the unit with a short lever which goes down to the wishbone).
The lead has a couple of grommets which locate it on a bracket just near the connector and also onto the strut and there should be another clip halway along the brake pipe that it clips into, finally you pop off the bleed valve cover and tuck the cable into the retaining loop for this...and put cap back on. basically the wire follows route of flexi brake pipe.
At the caliper end the sensor is, as I said an L shaped. imagine it as a capital L, about 3.5cm high with a foot of about 1.5-2cm. The cable comes in at the end of the foot (from bottom right of our L) Half way up on the front vertical of the L there is a pin sticks out, and near the top at the back of the L there is a bump which is the sensor surface.
Looking at the nearside caliper from above the sensor fits on the inside pad, the pin pushes tightly into the rivet which holds the antirattle spring (L is upside down with wire leading out towards strut, bump on sensor is facing disc and whole thing sits in recess in pad. When pad wears down the bump touches disc which wears it down, a link inside bump is broken which triggers brake wear signal. Problem is the sensor is a tight fit in the rivet head and is difficult to remove without breaking it. I managed by supporting pad and gently drifting pin out from reverse side but its probably worth getting a new one if you are changing pads, you will need a new one anyway this time but nothing worse than getting motor to bits and finding you need extra part...with no transport to get it :'(
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nice one robg, a picture certainly is worth a thousand words :)