Z3, 2.8 -98 brakes uneven?

[Kornknarr]

Dear forum,

recently my beloved car has shown a symptom that I'd like to have some help diagnosing. When I brake the onset of the brakes seem to be a bit uneven. I get a very short pull in the steering as if one side in the front does not brake at the same time as the other. After the short initial hesitation there is no problem and both sides brake normally. So apart from that short sideway-power that I feel in the steering wheel, and as a short hesitation in the pedal, everything is normal. It seems as it is more pronounced when the brakes are warm but I'm not sure about that and it does not happen all the time. What can it be?

Is it caliper-related? A bleeding problem? Bushings?

I had the car up yesterday but can not feel anything moving either calipers or bushings.

My guess is that it is time to change calipers and pads - the car is 12 years old and have seen a bit of braking. I am also not sure when it had a change of brakefluid. I've had it for a year only.

Grateful for any wisdom!

(A wonderful day here today by the way, had the car to work and found out that one of the teachers that I work with also had a Z3 on the parking - beautiful!)

[Zed Carer]

It could be that on one side the pads are not free to slide and so the free side moves before the one that is sticking. As a starting point I would remove the pads and calipers, clean everything, check the piston seals, etc and re-assemble with new Copa slip grease on the slides where the pads fit. You could do the brake fluid change at the same time if you think it needs it - normally a little clock sysmbol appears above the service lights when a change is due. After you've finished push the brake pedal down slowly, release, press down again and keep repeating until the pedal is firm. Mine is 13 years old (90,000 miles) and is still on the original calipers but I strip and clean the brakes each year.

We have been having a few days of Zed weather as well but mine only goes to the golf course now

[Kornknarr]

Thanks!

Sounds plausible. I don't have time this weekend to jack it up and do it, but will do as soon as possible and let you know what I found.

Thanks again!

Per

[Kornknarr]

Had time to jack up the car today. Cleaned up the caliper and greased it. Problem solved. But I did not really like to look of the piston so I think I'll go for a change of calipers and rotors before the car's winter sleep.

Thanks for the tip!

Per

[Zed Carer]

Had time to jack up the car today. Cleaned up the caliper and greased it. Problem solved. But I did not really like to look of the piston so I think I'll go for a change of calipers and rotors before the car's winter sleep.

Thanks for the tip!

Per

You are very welcome - luckily the Z3 brakes are quite easy to work on and basically the same system is fitted to my wife's Z4 and that makes life easier for me.

The next stage would be to remove the 2 bolts that hold the caliper (7mm Allen Key) - these fit through rubber sleeves that allows a flexible mounting for the caliper that can sometimes get siezed in one position. I just clean and grease the mounting bolts before refitting them. I just check the piston seal for any leaks or splits - the usual problem is that the piston can wear and a ridge forms that stops the piston moving fully back into the caliper. An alternative to new calipers is to use a refurbishment kit (new pistons, seals, etc), clean the caliper and fit the new parts - perhaps something to do whilst the car is asleep.

[Kornknarr]

Refurbish would perhaps be a good idea. Then I can sit with dreamy eyes and polish calipers at christmas. Would finally persuade my human lady that I've gone totally nuts (and bolts).
But then one needs to plug the brake pipes I guess? Any ideas on how to do that best?

Per

[BladeRunner919]

Refurbish would perhaps be a good idea. Then I can sit with dreamy eyes and polish calipers at christmas. Would finally persuade my human lady that I've gone totally nuts (and bolts).
But then one needs to plug the brake pipes I guess? Any ideas on how to do that best?

Per

You can buy clamps specifically for the job eg:

http://www.drapertoolbox.co.uk/draper-1 ... 2192-63256

They will clamp the hose shut without risk of damage, which you might get if you used a pair of locking pliers.

[Kornknarr]

By the way - have to agree on that the brakes are easy to work on. I have some experience from a diverse line up of old Peugots, Volvos, Fords, Citroens Saabs et cetera but these were the best so far!

Per