Brakes seized on mid journey
Discussion
No idea how this has happened as the car is being used once or twice a week, the brakes on my car have seized on. Not only that, but they have seized on mid journey.
First I knew was as I slowed at the end of a dual carriageway section and realised I was slowing down v quick. Got to a side street and that’s it. Stopped and stuck.
The only solution I can think of is to lose some brake fluid and gently drive using the gears and handbrake.
But any thoughts as to how this could happened??
First I knew was as I slowed at the end of a dual carriageway section and realised I was slowing down v quick. Got to a side street and that’s it. Stopped and stuck.
The only solution I can think of is to lose some brake fluid and gently drive using the gears and handbrake.
But any thoughts as to how this could happened??
Yeah, I left all that out in case there were any general pointers, but as you've asked...
1987 Porsche 928 S4, discs all round, conventional cable handbrake. No clues beforehand that something was awry.
I'm going back to have a look later and see if I can crack the two nuts where the brake lines come into the master cylinder to see if any pressure can be released.
1987 Porsche 928 S4, discs all round, conventional cable handbrake. No clues beforehand that something was awry.
I'm going back to have a look later and see if I can crack the two nuts where the brake lines come into the master cylinder to see if any pressure can be released.
finlo said:
Seized caliper, disc rubs gets hot expands then locks had it on the motorhome.
That would fit. It felt like a rear brake as I can go forwards, we’ll sort of, but not backwards. And the fronts were all looked at only a few months ago when I changed the pads and discs. The rears looked OK so I left them... Doh!Right, if that’s the case then it should just drive home OK now - all cooked down.
Will report in later...
Similar happened to me once in my old 300ZX. Only difference was I boiled the fluid and the pedal went to the floor, fortunately without hitting anything.
Stopped at a nearby pub, had an unplanned meal and a pint, by which time it had cooled down and it drove the 15 miles home at a crawl with no further problems.
Front 4 pot caliper had 2 seized pistons which was easily sorted with a seal kit.
Stopped at a nearby pub, had an unplanned meal and a pint, by which time it had cooled down and it drove the 15 miles home at a crawl with no further problems.
Front 4 pot caliper had 2 seized pistons which was easily sorted with a seal kit.
Went back to the car this evening, and a full cooldown seems to have done the trick. It rolled forward when the handbrake was released, so I used that to get me home.
Tried the brake pedal when I got home, and the first push was squishy, though by the third it was back to normal feel.
Anyway, parked up until I can get to the rears for a proper look.
Tried the brake pedal when I got home, and the first push was squishy, though by the third it was back to normal feel.
Anyway, parked up until I can get to the rears for a proper look.
I started having problems with blueing discs on my 89 S4 and as LarJammer posted it’s from the stainless steel plate that the brake pad slides against gets corrosion underneath it, it lifts up and the pads bind in the calliper. Fairly well known issue, most decent specialists can deal with it. Have a look on rennlist for a how to if you fancy having a bash yourself.
edit to add link
https://rennlist.com/forums/924-931-944-951-968-fo...
edit to add link
https://rennlist.com/forums/924-931-944-951-968-fo...
Edited by Huskyman on Wednesday 12th May 21:55
PomBstard said:
Thanks all. Well, it seems I can drive the car, albeit for about a mile before the brakes are locked on again. Booked in for a brake strip down and new hoses. Possible that the master cylinder is having a laugh too. As long as it’s not the servo, cos the engine’s in the way...
The engine in the way thing made changing the clutch master cylinder swap on my car a joyous experience on my 928 
IIRC correctly the brake lights are switched on by a pressure switch on the brake hydraulics, so if the brakes seize on and the brake lights come on then this could be the fault. PomBstard said:
Thanks all. Well, it seems I can drive the car, albeit for about a mile before the brakes are locked on again. Booked in for a brake strip down and new hoses. Possible that the master cylinder is having a laugh too. As long as it’s not the servo, cos the engine’s in the way...
What's the word them PomBstard? Must admit it sounded like a stuck-on caliper to me.Krikkit said:
PomBstard said:
Thanks all. Well, it seems I can drive the car, albeit for about a mile before the brakes are locked on again. Booked in for a brake strip down and new hoses. Possible that the master cylinder is having a laugh too. As long as it’s not the servo, cos the engine’s in the way...
What's the word them PomBstard? Must admit it sounded like a stuck-on caliper to me.Did have a chat though, and we just won't know until its up on a hoist and being stripped. Looking in the engine bay, there's no way to get that servo out with the engine in place - and having seen one out of the car, I can see why.
I'll keep y'all updated when I know...
Well, got it sorted this week. Brake master cylinder was the culprit - no problem with brake lines or hoses, or the servo - phew!. We’re not entirely sure of the mechanism of failure that caused the brakes to jam on, but oddly it was just the rears that were getting stuck.
Anyway, the 928 Doctor had already ordered one from Porsche Germany a couple of weeks ago when this first happened, so a spare was on hand.
Should note that this looked like the original master cylinder too - so that’s 35 years old…
So, just the A/C, springs/dampers, exhaust and wheels to go…
Anyway, the 928 Doctor had already ordered one from Porsche Germany a couple of weeks ago when this first happened, so a spare was on hand.
Should note that this looked like the original master cylinder too - so that’s 35 years old…
So, just the A/C, springs/dampers, exhaust and wheels to go…
GreenV8S said:
PomBstard said:
We’re not entirely sure of the mechanism of failure that caused the brakes to jam on
My guess would be scoring or crud preventing the piston from returning to the rest position.Gassing Station | Suspension, Brakes & Tyres | Top of Page | What's New | My Stuff