Technical Locked Front Brakes

[brucebp]

Reading some of these posts, you all seem so erudite and knowledgable on matters Sei I feel embarassed to ask, but, I'm stuck, in more ways than one.
Out driving today a braked to get a good look at a rather nice old Healey 100/6. Pulling away my little Sei was very sluggish and a couple of hundred yards on, stopped completely. To cut a long story short, the front brakes are hard on. I undid the bleed screw which freed the brakes, and drove home on gears and handbrake (I live in rural gloucestershire so not quiet as Kami-Kazi as it sounds). My problem is, what could be the problem? has anybody experienced this or have any ideas?

 

[rallycinq]

Collapsed flexi hose, possibly, but I doubt both would go together. Master cylinder seal turned in the bore?

Cheers

D

 

[custard]

as said was it one or both fronts?

 

[brucebp]

Seems to be both, both wheels were very hot, but I let the fluid out of the O/S front to get it going again.

 

[custard]

good news is if it is the master cylinder then these are around £20 new from fiat so not so bad

 

[fingers99]

Could very well be the servo. See this thread.

 

[levemircento]

if pads are worn all the way, then wheel cylinder may have come out too far and siezing on. possibly

 

[randomizered]

Never heard of that at all but does seem very odd!!!

have you tired to use them since? do they lock up again?

If they don't work now, if you slacked the nipples and drpress the pedal, does fluid come out?

The pads and discs look ok? regular service?

The backs can lock on if not properly adjusted or handbrake left partially on due to drum and pad expansion from the heat, but I have had my fornt burining several times under heavy braking and they just keep going.

I'd have thought a collapsed hose would cause lack of braking? Broken wall/expansion.

A seal flipped would surely cause total faliure not the opposite?! Something has to keep the pressure there for the brakes to be on, and I can't see a flipped seal would do it.

Cheers,


Kristian

 

[fingers99]

Don't mess about. It's important to proceed logically as here or you'll spend time and money getting nowhere.

 

[rallycinq]

I'd have thought a collapsed hose would cause lack of braking? Broken wall/expansion.

I have experienced the break up of the inner lining of a flexi hose causing a non return scenario.

A seal flipped would surely cause total faliure not the opposite?! Something has to keep the pressure there for the brakes to be on, and I can't see a flipped seal would do it.

Again, a similar, but seperate occasion where the seal had inverted and although the shaft was moving, the seal was in the 'brakes on' position.

Both might be wrong, but they are both bizarre incidents that I have had to diagnose.

Cheers

D

 

[richydraper]

i had caliper pistons sieze on my bike that cost me a lot of money but it was only one side my next guess would be sommin to do with the master cylinder as its the next thing inline from the calipers... personally i cant see it bein the vacuum assist as u can still brake without it (in a limited way) so id be having a vaguely educated guess at "mechanical" workings of the system.

 

[fingers99]

i had caliper pistons sieze on my bike that cost me a lot of money but it was only one side my next guess would be sommin to do with the master cylinder as its the next thing inline from the calipers... personally i cant see it bein the vacuum assist as u can still brake without it (in a limited way) so id be having a vaguely educated guess at "mechanical" workings of the system.

No guesses, please! Yer man should have a pdf of a logical way to proceed in front of him. Hopefully he's following it!