Freak Handbrake Issue

[Karma Supra]

Hi Folks..

The mrs had a scare on saturday morning in her MR2 when the drivers side brake seized. The handbrake was disengaged but that wheel stayed locked, by the time she had made it home the disk was glowing red, so I had to drop her off at work

I have heard of MR2s having rear calpiers seize handbrake wise, but was under the impression they were usually seized "off" I also gather that as opposed to the "usual" drum in a disk rear handbrake setup, the MR2s run a lever on the rear caliper that uses the brake disks, so I guess irs something to do with that that seizes?

The odd thing is that about an hour later I looked at the car, the handbrake had freed up and now seems to operate as normal... Unfortunately I couldn't get the wheels off to investigate as some idiot has over tigntened them.. I bent a toyota wheel brace trying to undo them!

From previous experaince here would you chaps suggest its the caliper at fault, or could the handrake line had seized/frozen solid further away from the wheel?? From experiance on other cars a seized caliper doesn't usually un jam with no intervention whatso ever!

[GIDDLEPIN]

Was it still freezing your way when it happened?

It could be moisture in the cable freezing up and not fully releasing the brakes.

[Karma Supra]

Yup that what my thought was, The cable frozen where it splits off on once side, but a bit back from the wheel, seems a bit far fetched to me, I have never heard of it hapening before! Is it a known fault?

[Parts-King]

I would imagine the heat from a red hot "glowing" disc would have melted any freezing action. I would think something has semi seized TBH. When you can, get a wheel off and check it out, it is quite likely the pads will be goosed now if it got that hot, maybe even melting some seals too! You can get new seals and pistons if required

Kingo

[GIDDLEPIN]

Happened here CLICKY that's why it sprang to mind when reading your post

I would imagine the heat from a red hot "glowing" disc would have melted any freezing action. I would think something has semi seized TBH. When you can, get a wheel off and check it out, it is quite likely the pads will be goosed now if it got that hot, maybe even melting some seals too! You can get new seals and pistons if required

Kingo

The cable is well clear of calipers and in the cold air stream so it is possible to be frozen for quite a while ;)

[Parts-King]

I'm not saying it's impossible, its just the MR2 calipers are famous for seizing up and a build up of salt/corrosion is much more likely to semi-seize any part of the caliper/handbrake links. With a glowing disc, it's likely to have caused further damage, whatever the cause, further inspection is required, just to make sure nothing melted

Kingo

[Karma Supra]

I would imagine the disk is probably pringle shaped at least... although I drive it down the drive and back and didn't notice any juddering I coun't see much through the factory wheels but the pads looked like they still had some meat on them.

Oh well... decent 21mm socket orderd so I can get my breaker bar onto it, hopefully that and WD-40 and all the wheel studs will stay intacked!

I remember the seller saying it had had new rear tyres the day before we bought it, clearly the shop that fitted then should not be allowed near any cars, the jacking points were lightly bent and the wheels are WAAAAAAAAAAAAAAAAAAY over torqued.

I know about rebuilding calipers, but I have never done one with the daft handbrake arm, how does it work?

I assume its nothing to do with the hydraulics themselves. Does it operate the actual piston manually, or does it apply presure some other way? (Bearing in mind I have not even looked at it yet, and I have touched the rear brakes on my previous three MR2s lol)

If it was my car I'd not stop short of rebuilt calipers all round, new disks and pads, braided SS lines anda new handbrake cable... but its not, and the mrs doesn't have the money to get it done "properly", there is also the pressing matter of needing a new clutch, and four new tyres t contend with, as well as a !Removed! good service!

[GIDDLEPIN]

If the MkII is the same as mine it will ratchet up with brake application CLICKY

[Parts-King]

I know about rebuilding calipers, but I have never done one with the daft handbrake arm, how does it work?

I assume its nothing to do with the hydraulics themselves. Does it operate the actual piston manually, or does it apply presure some other way? (Bearing in mind I have not even looked at it yet, and I have touched the rear brakes on my previous three MR2s lol)

yes the cable operates a crank at the bottom of the caliper, and that winds the piston out via a sort of threaded bolt, I would upload a picture but I cant access the picture library at the moment, will upload one later (If I remember )

Kingo

EDIT: Parts listing picture

[cfc1]

It's not nececesarrassessacirily the garage who over torqued the nuts, the heat from the siezed break could have caused them to tighten themselves up. There are a few makes of car out there that I deal with every day where you would think they have been over torqued... Audi's, Vauxhall's, VW's and Renault imeaditly spring to mind.. and with the poor quality of the renault stud these have a tendancy to shear off when you attempt to loosen them.. it doesn't take much.

Try tightening the nut a very small amount (being carefull not to completely over do it) before trying to loosen it.. it sometimes helps them to release their grip a little.

[Karma Supra]

Cheers Kingo, that makes sense, I had a radio controlled car with a similar setup a few years ago ;) I'm not suprised they seize! Edit: cheers for that!! good old EPC :)

Cheers Les for the pics, I think the setup looks a little different though... I'll confirm when I get the wheels off and have a proper look for the sake of the search engine ;)

Davy, I agree, however the wheels were equally tight on both sides, combined with evidence of improper jacking and the fact that one of the tyres is a winter tyre, I'm going with "idiot garage". The two nuts I managed to undo (one on each side) whet with a couple of bangs and a loud creak. I'll give that a go if I hav eprobems once I have a suitable socket.