Mk2 172 20% Imbalance in front brakes

[MattR172]

On Thursday i had my first MOT which my 2003 172 passed with no problems. On the notes the mechanic gave me it said there was a 20% imblance in the front brakes. Im going to replace my pads soon because he also mentioned that they are wearing now. Will replacing the pads sort out the brake problem or will it have to be done separately?

What exactly is involved to correct brake imbalance??

Many Thanks

Matt

 

[edde]

I'd guess he means one sides pulling a bit harder.
Nothing much you can do unless you fnacy replacing all the calipers.
Best when you change the pads to check for free movment of the caliper.
Mine always wear slightly unevenely.

 

[MRBILLYUK]

On Thursday i had my first MOT which my 2003 172 passed with no problems. On the notes the mechanic gave me it said there was a 20% imblance in the front brakes. Im going to replace my pads soon because he also mentioned that they are wearing now. Will replacing the pads sort out the brake problem or will it have to be done separately?

What exactly is involved to correct brake imbalance??

Many Thanks

Matt

My 172 failed on 26% brake imbalance , anything over 25% is a fail .I just took off the caliper , pushed out the piston , greased it with a little copper grease and it past

 

[Jones]

I bet you its the pads

 

[MRBILLYUK]

I bet you its the pads

And why would the pads cause brake imbalance ? Brake imbalance is when one caliper is working better or harder than the other side i.e not braking at the same rate . It wouldn't matter if one set of pads had 4 mm left on and the other had 7 mm they both would brake evenly if the calipers were working correctly .

I'll put money on it being one of the pistons in the calipers is sticking slightly .

 

[Jones]

And why would the pads cause brake imbalance ? Brake imbalance is when one caliper is working better or harder than the other side i.e not braking at the same rate . It wouldn't matter if one set of pads had 4 mm left on and the other had 7 mm they both would brake evenly if the calipers were working correctly .

I'll put money on it being one of the pistons in the calipers is sticking slightly .

well on every car i have ever worked on that had a brake imbalance it was the pads. If one of the pistons in either caliper was sticking then you would get brake binding where effectively the brake is on all the time.

It be thee pads i tell thee

 

[MRBILLYUK]

well on every car i have ever worked on that had a brake imbalance it was the pads. If one of the pistons in either caliper was sticking then you would get brake binding where effectively the brake is on all the time.

It be thee pads i tell thee

Not in my case i tell thee . Was the caliper , pads were fine .Stripped down , greased , put back together , as good as new and no brake imbalance anymore

 

[MattR172]

Yeh, the mechanic mentioned if it had been over 25% imbalance he would have had to failed it. How do they check for brake imbalance in an MOT then?

 

[edde]

Yeh, the mechanic mentioned if it had been over 25% imbalance he would have had to failed it. How do they check for brake imbalance in an MOT then?

They have a rolling road type thing they get the car to brake the two seperate rollers if one brakes slows the roller down quicker then thats the difference.

 

[Dan@SJM]

it also measures the braking effort in kg's.

 

[MattR172]

So would your first idea be to get my pads changed then check the imbalance after that?

 

[MRBILLYUK]

They have a rolling road type thing they get the car to brake the two seperate rollers if one brakes slows the roller down quicker then thats the difference.

So if one caliper is working better than the other i.e pulling more efficiently you will have brake imbalance . If the piston is tight , or slightly seized in the caliper then it won't operate like a good caliper would .
I'd take the caliper off , leaving it connected to the brake hose , press the brake pedal so the piston pops out of the caliper and apply a thin film of copper grease inside the caliper .

Make sure you don't get any dirt , grit etc inside the caliper or on the piston itself !

It can be a bit fiddly gettin the piston back into the caliper , put a little bit of grease around the dust seal to help it back into the hole , make sure you've got the piston square onto the hole and you should be able to press it back in with your thumbs .
Make sure you have plenty of spare brake fluid on hand and a clamp for the hose ,not essential but minimises fluid loss. Then don't forget to bleed the caliper .

Jobs a good un

 

[Dan@SJM]

i wouldnt pop the piston out. just wind it back in, then press the brakes slightly so it slides out, then back in and so on, just dont let it pop out.

 

[MRBILLYUK]

So would your first idea be to get my pads changed then check the imbalance after that?

If your pads are worn then change em . You'd have to get the car tested on the rollin road again to check if there is still brake imbalance, they might do it for free if you ask em nicely

 

[MRBILLYUK]

i wouldnt pop the piston out. just wind it back in, then press the brakes slightly so it slides out, then back in and so on, just dont let it pop out.

^^^^ why not ? ^^^^