Disks - and exhaust

Gareth · Post by **Gareth** » Wed Feb 01, 2006 3:30 pm

Put my car in the garage for 10 days. Took it out but the brakes were stuck on until a little 1st gear persuasion. So the brakes were lumpy and sounded bad. 5 days of going to work and they got better but I noticed today that the front and rear left disks are clean (you know where the pad has touched but the rear right is still rusty. I don't know if the calliper is jamed of what.

Any ideas.

Cheers

G

Rich H · Post by **Rich H** » Wed Feb 01, 2006 3:34 pm

I'd whip the wheel off and check the pad thicknesses and freedom of movement of the claiper. Only way to be sure.....

Gareth · Post by **Gareth** » Wed Feb 01, 2006 4:19 pm

Yup, definately seized. Must be the piston.

Post by **Shug** » Wed Feb 01, 2006 4:41 pm

Not the piston - same problem I believe JJ was having.

The rear caliper actually floats - there is only one piston, so the whole of the body must move on a slide to keep the pad contact even. Sounds like this slide has jammed. Have a look behind the caliper - the bottom mount bolt has a rubber concertina boot behind it - check that it's not split.

If it's not, then the slide will just be jammed and need a little 'gentle' persuasion - if you've only been commuting, the likelihood is that there's not been enough pressure to free it. Take it to a private test track and do several hard stops. If this doesn't free it, you might have to get physical with hammer/wood - but be careful!

If the boot has split then the seal kit is available from these guys:

http://www.classicbrakes.co.uk/

Discussed on the thread about back brakes rattling today.

HTH

Post by **Shug** » Wed Feb 01, 2006 4:45 pm

Oh, and worth mentioning that you'll get this sort of thing at this time of year, as the roads have so much sh*t on them that you end up not using the brakes anywhere near as hard as the summer - so any crud from the roads that gets in these slides has an even easier job of jamming them. Especially as the majority of the Elise braking force is on the fronts.

Rich H · Post by **Rich H** » Wed Feb 01, 2006 4:46 pm

Possibly not, jack it up and put the hand brake on, see if the wheel is free to rotate, IIRC the handbrake uses the same piston. If the piston was stuck then you would get no braking at all on that side. It could be the caliper guide pins that have stuck. Otherwise remove the wheel, pads and disk and have a look. Probably worth trying to re-set the handbrake mechanism by winding in the piston (Not done this so can't vouch for what happens) The caliper should move in and out along the guide pins, mine was firm but smooth (Fnarr Fnarr) in operation. I don't know if you can get in to clean it all up.

I didn't get any further than this when I changed my brake hoses.

Anyone got any better ideas?

HTH
Rich

Rich H · Post by **Rich H** » Wed Feb 01, 2006 4:47 pm

Beaten to it....

Post by **Shug** » Wed Feb 01, 2006 4:50 pm

Aye rich - to add to my meanderings above, the upper bolt has a concertina boot as well, of course.

Quick and easy way to tell if it's piston or slides is feel the back of the disk. If it's rusty too, it's the piston, if it's not it's the slides.

Gareth · Post by **Gareth** » Wed Feb 01, 2006 4:50 pm

Cheers guys but I have no fookin idea what you lot are on about. Only thing I've ever done mechanically is change brake pads and suspension (with help from Tim)

Post by **Shug** » Wed Feb 01, 2006 4:52 pm

Guide to pads here:

http://www.elise-faq.info/content/brakes/padchange.php

Shows the rear caliper, so it might give a better idea what we're rattling on about.

Rich H · Post by **Rich H** » Wed Feb 01, 2006 4:52 pm

Shug wrote:Quick and easy way to tell if it's piston or slides is feel the back of the disk. If it's rusty too, it's the piston, if it's not it's the slides.

G - do this. Easy to check and will diagnose the problem.

mac · Post by **mac** » Wed Feb 01, 2006 5:28 pm

Gareth,

You car is only just out of MMC - take it back and tell them to fix it!

brake pads are a wear and tear item (by definition they are supposed to run out) but the brake mechanisms should be covered.

Gareth · Post by **Gareth** » Wed Feb 01, 2006 6:05 pm

Some heavy braking on the way home seems to have fixed the problem but is it just my luck with brakes as the same happened on the S1 - I'm getting the knocking again and not only that it's like I'm hearing the disk going round. Goes away when I brake.

I'm not wanting to feck around with buffer pads....

Post by **Shug** » Wed Feb 01, 2006 6:09 pm

Come on, would take an hour tops! Clean the calipers properly and use the proper Lotus buffer pads and you'll not have a problem.

The noise from the disks is probably just the fact that they've had a bit of rust on them - it'll go away if it's used regularly and properly

Gareth · Post by **Gareth** » Wed Feb 01, 2006 9:26 pm

I think the exhaust maybe hitting the heat shield...possible??
If so I believe I can bend it a little???