Rear brake binding

Sharpm · Post by **Sharpm** » Sun May 05, 2013 8:15 pm

My rear drivers side calliper on my s1 is binding and heating up the wheel after only a short drive.

When its cool the wheel spins freely but after a run its stuck solid.

When I bought the car last year the calliper was brand new as it was replaced for the mot.

I've just rebuilt the rear suspension so everything is new and the calliper moves freely, the pads must just be dragging enough to heat up the disc and cause it to bind. I've tried to back off the handbrake but that's not made it any better.

Looks like ill have to try a new calliper, unless anybody has any other suggestions ??

Anybody got a rear drivers side calliper lying around I could try or buy ??

Thanks

robin · Post by **robin** » Sun May 05, 2013 11:07 pm

I would be tempted to disconnect the handbrake cable completely, wind back the piston and refit leaving the cable off and see whether it still binds. If the brake still binds then look at the sliding bolt to see if it's corroded - if the rubber hood on that bolt has been damaged you might find some corrosion in there.

Cheers,
Robin

Sharpm · Post by **Sharpm** » Thu May 09, 2013 11:34 am

no corrosion as the caliper is almost brand new and tried running with the handbrake disconnected and the caliper wound in but no difference.

i have however cured it last night by winding back the piston fully while bleeding at the same time - quite a bit of air came out so assuming this was expanding when hot and applying the brake.

thanks,

Scottish Scrutineer · Post by **Scottish Scrutineer** » Thu May 09, 2013 1:32 pm

Sharpm wrote:
i have however cured it last night by winding back the piston fully while bleeding at the same time - quite a bit of air came out so assuming this was expanding when hot and applying the brake.

thanks,

Good find.

Sent from my iPad using Tapatalk
Renny

Sharpm · Post by **Sharpm** » Thu May 09, 2013 10:15 pm

Not quite, it worked for a day, but now its back to its old tricks and heating up again !!

Took the offside rear wheel off and checked the runout of the disc with a dial gauge which was quite a bit (mmc) so swapped the disc over with the nearside one which has no runout.

Strangely enough the nearside disc now has runout on the offside, so conclusion is a slightly buckled hub - maybe a kerbed wheel in the past.

the runout might be enough to rub the pads on and off the disc resulting in it heating up when cruising on the motorway.

Next step is to try another hub - anybody got one please ?????

Thanks

tut · Post by **tut** » Fri May 10, 2013 8:47 am

http://www.ebay.co.uk/itm/Lotus-Elise-S ... 460ef14d98

Difficult to find used ones, I just had the same problem.

tut

woody · Post by **woody** » Fri May 10, 2013 9:14 am

I have a couple, but they're both still built into MG TF rear suspension assemblies. Eliseparts can supply stronger ones new.

Are you sure the hub face is clean and free of contamination? Only needs to be a couple of thou there to give a bigger run-out at the disc edge.

Sharpm · Post by **Sharpm** » Thu May 23, 2013 4:37 pm

ok this is really p***ing me off now.

firstly - I was sure it wasnt the caliper at fault, as it was new one week before i bought the car in aug last year, i still have the receipt from the specialist in southampton and its an original lotus part too.

then i was convinced it was the hub buckle that was the problem - it was buckled slighlty as the new one ive fitted has no buckle, but has the problem gone away - NO

so, im back to where i started and it must be the braking system, however i had a look at the nearside caliper and it was very very difficult to wind back the piston to fit new pads, so maybe the reluctance of the nearside pisotn to move is affecting the operation of the offside, as the system is split front to back not diagonally as on some cars ??

anyway, who knows, all i know is that i need to try a replacement rear caliper either offside or nearside or both to determine where the problem lies before i splash out and buy a new caliper as im not sure which one is the problem !!

so anybody got a rear caliper for an S1 either side or both that i can buy or try to determine where the problem lies ??????

woody · Post by **woody** » Thu May 23, 2013 6:03 pm

Try Junks on SELOC. Got a low miles pair from him for £150 a few months ago.

robin · Post by **robin** » Thu May 23, 2013 10:05 pm

Have you worked out which of the pads is binding - is it outside or inside? The caliper floats on a pin - even if the caliper is new perhaps the pin is old, bent or corroded?

Cheers,
Robin

Scottish Elises