Front left brake is grabbing more than the right front brake - solved abs pump failure

davidxzy

davidxzy

Can't figure this one out. When I do an emergency stop, the car pulls to the left. I checked all the wheels by putting a clamp on the brake pedal so that the brakes are just starting to bite, jacking each wheel up one at a time and rotating them. Sure enough the front left wheel needs much more effort to rotate by hand compared to the other wheels. So how can the left brake caliper be applying more pressure? I have replaced all the slide pins on both front calipers and fitted new pads. Maybe I've got it the wrong way round. Maybe the right caliper has some obstruction. I've forced the piston out on the right side but it looks fine with no rust and it moves freely in and out. Unless the brake hose is bad.
 
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Twincam-Alex said:
This sound more like a sticking caliper piston.
When fitting the new pads did the pistons push in easily?
If it took effort then its time to replace both calipers.
Click to expand...

The left piston pushed in quite easily using a large C-clamp. But I remember the right piston (driver side) not going in at first as though it was seized and then after applying more pressure on the C-clamp it went in. I pushed the brake pedal to extend that particular piston almost all the way out and found no rust on it. Unless the seal has become dried out and causing the piston to seize. I've got a new piston and seal kit and will attempt to replace both pistons and also the brake hoses.
 
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Problem solved. New piston and seal fitted. It was an oxidized brake piston and seal caused by 10 year old brake fluid (which has now been flushed). I have never heard of this oxidation problem. Only found one mention of it on another forum:

Code: 
"Seals might be OK but the dust covers shot and a bit of corrosion.

First and cheapest thing is caliper off and block off wood and slowly pump brake if only 2 or 3 pistons come out there lies the piston with issue.

Keep pumping till it pops then clean up the face of the piston if needed. retract and and try again if this does not free it enough then its piston out and proper clean up and maybe a seal replacement then bleed.

If any water gets in the piston wall just cakes up with oxidisation post seal and jams it. After rebuilding a set it takes only a little build up to cause them to sieze or run slower than the other pistons."

IMG_20221116_114256.jpg

And I almost forgot to clean the claw part of the caliper as a build up of corrosion here can cause the pads not to seat properly.

IMG_20221116_122518.jpg
 
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davidxzy said:
Problem solved. New piston and seal fitted. It was an oxidized brake piston and seal caused by 10 year old brake fluid (which has now been flushed). I have never heard of this oxidation problem. Only found one mention of it on another forum:

Code: 
"Seals might be OK but the dust covers shot and a bit of corrosion.

First and cheapest thing is caliper off and block off wood and slowly pump brake if only 2 or 3 pistons come out there lies the piston with issue.

Keep pumping till it pops then clean up the face of the piston if needed. retract and and try again if this does not free it enough then its piston out and proper clean up and maybe a seal replacement then bleed.

If any water gets in the piston wall just cakes up with oxidisation post seal and jams it. After rebuilding a set it takes only a little build up to cause them to sieze or run slower than the other pistons."

View attachment 79246

And I almost forgot to clean the claw part of the caliper as a build up of corrosion here can cause the pads not to seat properly.

View attachment 79247
Click to expand...
Brake fluid being hydroscopic can corrode the internals. One of the reasons why car manufacturers recommend changing every 2 years.
Hopefully your all sorted for a few more years.
 
fookmyoldboots said:
Good work. Thanks for the updates.
Click to expand...
Well it all went badly wrong. Since fitting the new piston and bleeding the brakes the brake pedal now sinks to the floor and it is necessary to keep pumping the brake pedal to stop the car. I wonder if the master cylinder has decided to pack in. I will check the new piston seal I put in maybe I have damaged it when inserting the new piston.
 
davidxzy said:
Well it all went badly wrong. Since fitting the new piston and bleeding the brakes the brake pedal now sinks to the floor and it is necessary to keep pumping the brake pedal to stop the car. I wonder if the master cylinder has decided to pack in. I will check the new piston seal I put in maybe I have damaged it when inserting the new piston.
Click to expand...
Once you pump and get a firm pedal if you hold it does the pedal slowly sink?
If it doesn't sink there is probably air in the system.
If it does slowly go down there is probably a leak.
Recheck the calipers for leaks, I've never had success in replacing the seals thay always leak!!
Also check the rear wheel cylinders if you haven't already done so.
 
Twincam-Alex said:
Once you pump and get a firm pedal if you hold it does the pedal slowly sink?
If it doesn't sink there is probably air in the system.
If it does slowly go down there is probably a leak.
Recheck the calipers for leaks, I've never had success in replacing the seals thay always leak!!
Also check the rear wheel cylinders if you haven't already done so.
Click to expand...

Yes, if I pump and get a firm pedal and hold it the pedal sinks slowly to the floor. I will check all over for leaks and report back.
 
Went out for a few miles drive last night and all the time the brake pedal was doing the same thing - Pump the pedal and then hold it and the pedal sinks to the floor. Checked all over no leaks. Brake master cylinder fully topped up and no lose of fluid. So I remembered what my old boss said "if you can't go forward, go backward". (I've only had one official job so that's how I remember what he said) So that's what I did and decided to put the old piston and seal back into the caliper. That's when this little rubber ring popped out of the piston chamber. I must have sheared off part of the rubber boot when installing the piston.

IMG_3977.JPG
 
davidxzy said:
Went out for a few miles drive last night and all the time the brake pedal was doing the same thing - Pump the pedal and then hold it and the pedal sinks to the floor. Checked all over no leaks. Brake master cylinder fully topped up and no lose of fluid. So I remembered what my old boss said "if you can't go forward, go backward". (I've only had one official job so that's how I remember what he said) So that's what I did and decided to put the old piston and seal back into the caliper. That's when this little rubber ring popped out of the piston chamber. I must have sheared off part of the rubber boot when installing the piston.

View attachment 79269
Click to expand...
Did you coat the new piston and seals with fresh brake fluid before installing?
Red brake grease is ideal for caliper and cylinder reassembly.
 
Twincam-Alex said:
Did you coat the new piston and seals with fresh brake fluid before installing?
Red brake grease is ideal for caliper and cylinder reassembly.
Click to expand...

Yes I put brake fluid on before installing. I have red rubber grease but didn't use it this time in case it was doing something weird. I just reverted back to the old piston and seal.

update: fitted old piston and seal and it made no difference. I have no clue what's going on with the sinking brake pedal. I have booked the car into the garage for repair, so let's see next week what the problem was if they can fix it. I told the garage he may need a nissan scanner to fix the brakes and he said no.
 
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davidxzy said:
Yes I put brake fluid on before installing. I have red rubber grease but didn't use it this time in case it was doing something weird. I just reverted back to the old piston and seal.

update: fitted old piston and seal and it made no difference. I have no clue what's going on with the sinking brake pedal. I have booked the car into the garage for repair, so let's see next week what the problem was if they can fix it. I told the garage he may need a nissan scanner to fix the brakes and he said no.
Click to expand...
Keep us posted. It will be beneficial to see what the outcome is.
 
Twincam-Alex said:
Keep us posted. It will be beneficial to see what the outcome is.
Click to expand...
The garage informed me today that they are pretty sure it is the abs pump. He said he might not be able to find the part and it won't be cheap. I looked on ebay and they are as cheap as chips. So I will probably collect the car tomorrow and pay him for the diagnostics. I will probably have to repair it myself unless he can source the part and quotes me a reasonable price, which I doubt.

So my initial problem of the car pulling to the left when braking seems to be down to the abs pump and not a sticky piston on the right caliper. The garage also said the left front brake was the only brake getting full power.
 
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The garage are going to fit a new abs module. The part will cost £1000 and it will take at least a week as the part is coming from Europe.

In total it will cost around £1200 as they have already done some work on the car such as fitting a new control arm and bleeding / testing the brakes to find the abs pump problem. I am past caring as the car has no MOT and I have spent a lot of money / time on it replacing tyres and brake parts. I just want it back on the road. I know some people would say you can just buy a abs pump online for £50 and do it yourself, but what if it is clogged up and my car fails its MOT again? This way the garage have the car off the road, so no need to worry about the police catching me without an MOT. Plus, the mechanics will make sure the new one is fitted correctly and works. And the garage will issue a fresh MOT certifcate after they have fitted the new abs module. And it takes the stress away from me as I am sick to death of fixing the car and worry about passing an MOT.
 
davidxzy said:
The garage are going to fit a new abs module. The part will cost £1000 and it will take at least a week as the part is coming from Europe.

In total it will cost around £1200 as they have already done some work on the car such as fitting a new control arm and bleeding / testing the brakes to find the abs pump problem. I am past caring as the car has no MOT and I have spent a lot of money / time on it replacing tyres and brake parts. I just want it back on the road. I know some people would say you can just buy a abs pump online for £50 and do it yourself, but what if it is clogged up and my car fails its MOT again? This way the garage have the car off the road, so no need to worry about the police catching me without an MOT. Plus, the mechanics will make sure the new one is fitted correctly and works. And the garage will issue a fresh MOT certifcate after they have fitted the new abs module. And it takes the stress away from me as I am sick to death of fixing the car and worry about passing an MOT.
Click to expand...

Quote; “I am sick to death of fixing the car and worry about passing an MOT”

The joys of cheap banger motoring as some of us petrol heads actually enjoy the challenge of amateur DIY improvising, adapting & overcoming the snags that inevitably crop up to be dealt with by me @ at marginal minimal overall costs.

The joy satisfaction of keeping my 26 year old banger K11 going with just routine consumable maintenance parts with my simple minded efforts & long may it continue onwards & upwards. ;)
 

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