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MG MGF Technical - Brake lock-up

After braking fairly hard in my Trophy the (Bembro) brakes stayed on. The pedal was solid, but after an hour or so released by itself. The problem has not re-occurred, but I'm driving on tip-toe now in case the problem repeats itself. Anyone experienced this before?

Brembo? You sure they are not AP? Sounds like you may have a leaking seal on the caliper. You can get service kits from AP direct. Rob Bell any idea's?
DJC Dorrell

Definitely AP Duncan.

Did both sides lock on JH?
Rob Bell

Yes, both sides locked, maybe even all four. I've noticed since the incident that the brakes sometimes bind a little, if I let the car roll to a halt after braking there is occasionally a slight retarding effect, with no tendency to veer, but I think that this is normal, or am I being paranoid?

Don't spose you have been fiddling with the brake switch?

It sounds like you have risidual pressure left in the system caused by the pedal not returning compleatly
Will Munns

Also - do you have ABS?
Will Munns

Servo, master cylinder or cross-rods under bonnet seizing?

I think that this is a very worrying development JH. As both calipers locked, it would suggest something wrong with the braking hydraulics, servo or mechanical linkage to the pedal as Tony suggests.

Common sense says that this should not be ignored, and it may be a good idea to get the car trailored to a specialist familiar with braking systems. Given your location, I'd go for Brown and Gammons or Techspeed motorsport (where my car is currently residing as we speak!)
Rob Bell

(no ABS on the trophys .... i think ... well, not that i've noticed on mine)

When I was in crawling traffic a couple of days ago with the roof down I thought that my calipers weren't fully disengaging .. the problem seemed to have gone away since the auto-electrician fixed the brake switch to cure my flickering brake light problem.

I've suffered with brake problems in a past car - best to get the experts in right away.
N McNamara

Yes, the brakes are ABS and no,I haven't been fiddling with them. I suspect that you are right in suggesting the servo or master cylinder. I was rather hoping that someone had seen this problem before, but I think that this is probably beyond my tinkering skills, so I will have to take the car to a specialist, as suggested. Do you have a phone # or web address for the businesses that you named, RB? Thank you all for your interest, any further comments would be welcome.
J. Hawkins

Brown and Gammons:


Best use the telephone for Techspeed - chat to Roy: 01926 632066
Rob Bell

Had the same problum on my old 1600E Cortina many years ago, it was the diaphram in the servo, it started to swell due to engine fumes being drawn in and rotting the rubber diaphram. It might be worth checking the servo vacuam none return valve as this can cause the fumes to get in and do damage.
Brian howarth

This thread was discussed between 08/08/2005 and 09/08/2005

MG MGF Technical index

This thread is from the archive. The Live MG MGF Technical BBS is active now.