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#1 Naughty front brakes
Posted: Fri Jan 20, 2012 4:50 am
by ralph kirsten
I drive a 1964 S1 FHC ... I did a total restore about ten years ago, recently the front brakes tehd to lock up (don't release after application) I then have to release them by opening the bleed screw to release pressure.
I must also admit that I fell into the trap of taking "expert" advise and first filled the (dual servo ststem) with silicon fluid... which I soon had to get out by continual bleeding and replacing with DOT 4.
Question: ... could it be that these two don't like each other and have caused swelling or damage, do I need to strip the whole system and replace ALL hoses and seals?
Ralph
#2
Posted: Fri Jan 20, 2012 11:16 am
by christopher storey
Ralph : you should not need to strip the system. The usual cause of the particular symptoms you cite is that the brake hoses have suffered internal degradation causing internal collapse of the hose bore. This then acts as a one-way valve and traps the line pressure between the site of the collapse and the caliper . A renewal of both front hoses should cure this
The other possibility, which more usually causes the more subtle problem of the the brakes sticking on for only two or three seconds before they release themselves, is that the shuttle in the servo master cylinder, as opposed to the pedal master cylinder , is sticking , but this rarely in my experience causes a total lock up of the type you describe. Edit : I have just realised yours is a 3.8 which would not usually have the remote servo , although you describe yours as "dual servo"
#3
Posted: Fri Jan 20, 2012 5:50 pm
by ralph kirsten
Hello Christopher
Thank you for your prompt responce, I have had the rubber hoses on my MGA cause brake problems, so I should have started there...
I have a 1965 S1 4.2 with dual line servo (vacuum booster with tandem slave cylinder) master cylinder with booster reaction valve (two fluid reservoirs)
I will start asap and let you know which one was naughty.
Thanks again for your help... If you come to S.A. we live near the Kruger Park on a private Nature Reserve with comfortable beds.
Regards
Ralph
#4
Posted: Sat Jan 21, 2012 3:01 pm
by ChrisC
I agree with Chris.... the brakes on my TVR seized on (and stayed on) producing much smoke and losing my grin.
I replaced both front brake calipers and only when that made no difference did i discover that it was a collapsed rubber hose which would have been MUCH cheaper :(