Warm OSR and NSF rims after driving.

[Johnmed]

Hi all.

Recently changed my rear pads after the mechanic told me at MOT time they likely only had a few thousand miles left. Was simple enough, but I remember the OSR piston was very tight when compressing, the NSR on the other hand compressed easily. I didn't undo bleed nipples on either but did undo the cap from the filling reservoir during the process.

Fitted Brembo pads and they came with new sliders and screws. Thought no more about it. Bedded the brakes in and have been driving gently since. I haven't done many miles since, admittedly. The EPB now actuates much quicker than recently (thicker pads).

Anyway, after faffing about with VCDS as per Rosstech's instructions (and measuring the thickness of the pads and calibrating accordingly) when replacing rear pads, I have been checking the wheels to see if all is well.

OSF and NSR wheels are stone cold, NSF and OSR wheels are warm. Not hot at all, just warm. I've experienced my old A2 and the wife's Honda Jazz's rear calipers both seizing, and their wheels got HOT.

I'll jack the car up tomorrow and make sure all wheels spin freely, is there anything else I should do?

Could the two warm wheels' warmth be connected, as in on the same system?

Thanks in advance

John.

[Johnmed]

Little update, rear OSR caliper was well and truly seized. Could barely turn the wheel. Have replaced it today. Inevitably I now have air in the system, and I have bled all four calipers but still a spongy brake pedal. D'oh.

Anyone have any tricks to further remove air?

[paulrstaylor]

I used a vacuum extractor to suck the fluid through..... Clip it onto the nipple, open it and wait until the bubbles stop

[Johnmed]

Hi Paul. Thanks for that. I've not used a vacuum kit. I lent my trusty Eezibleed kit out a while back and never saw it again. Can't bring myself to buy another. But I did pick this up:


http://www.halfords.com/workshop-too...h-bleeding-kit

It's pretty good TBH. Bled the brakes in a sort of Z formation (if seen from above) starting with NSF and ending in OSR if that makes sense. Firmed the pedal up a good amount. I think I will repeat this tomorrow, flushing the old fluid out as I go.

What's puzzling me now is the NSF wheel still gets like warm to the touch after a drive. But it's brakes aren't dragging. I've had all the wheels spinning off the ground, and they're all as free as each other.

I wonder if a warm bearing could cause this, -nod not have been flagged up at MOT, nor have any other symptoms...

[paulrstaylor]

I suppose it is possible, but I'd of thought you would of heard it grumble. My money would still be on a sticky caliper, have you striped it down or just soon the wheel of the ground?

[Johnmed]

Haven't stripped it down, no. Just spun it off the ground. I think you're likely right. I'm just a bit confused as to why it's luke warm like the other was, but the other was seized on quite badly, so you could barely spin the wheel. I will investigate further tomorrow. Thanks again.

[mannyo]

Maybe in intermittently sticking slider pin, had that on my old D2 which would be ok most of the time and then just fail to release properly. My local indy garage stripped it all down, cleaned it all up and put it back together and never had the problem again. The symptoms were just like yours, except sometimes it would be ok.

[mattylondon]

Hi John,

I would certainly remove the caliper and carrier and give them a clean as a preventative measure. If you fancy popping the piston out you can replace all the seals with a kit. If your wheel is still heating up it isn't the caliper.

[Johnmed]

Thanks Chaps. All good advice. Thanks.

[Johnmed]

Think I've cracked it now. Took the caliper apart, the piston moves freely, rubber looks great. But the slider pins were in a right state. And all of it was caked in brake dust. Wire brushed it all, cleaned and copper greased it all and the wheel spins even more freely now.

I've not been for a test drive, but, fingers crossed I've sorted it. Thanks again all.