Sticking brake

[Martin White]

Hi All

My 1976 1500 spitfire seems to have a stuck on brake. If I manage to get the caliper off and remove the piston. Is it then a case of fitting new seals or do I need to be taking anything else into account?

Not tackled brakes before so any advice welcome. I also assume I just need to bleed the hydraulic fluid from the side that I am working on.

Thanks in advance for any suggestions

Martin

[Peter Truman]

Is it stuck on all the time or random

 I had trouble with the brakes on my Sprint sometimes it would vehemently pull to the left the cause was the robber brake hose to the caliper internals were failing causing a reflux valve set up ie the pressure couldn’t release

[johny]

Hi Martin, how did you detect the sticking brake and was it after a period of no use? If you get the caliper off and remove the pads you might get away with just exercising its pistons by pushing them back in using a g clamp (careful that the fluid you push back doesnt overflow the reservoir!) then bring them out again using the pedal and so forth. Obviously DONT over extend the pistons so they pop out (very messy) and you might need to clamp one with the g clamp to ensure only the other moves... 

[Wagger]

First, just take the wheel off and use mole grips to force the pads away from the disc. I then jam a motorcycle tyre lever between piston and pad and lever it back further. Then have a friend press the brake pedal down and up as you pull the lever back and forth. If this loosens it, you may be able to remove the dust cover, with the pads out, and insert the protective grease after cleaning it.

This may not be a permanent fix if it works at all. However, I have done this on other cars with four pot calipers and kept all going for a season, then attending to it during the Winter.

If you have a collapsing flexible pipe, it will act lke a valve and the brake will stick ON, but releasing the bleed nipple should remove pressure in the caliper. If you have to replace anything it is best to bleed the brakes all round using new fluid to push the old out.

[Martin White]

Thanks all that is really useful info. I was coming back from a car show and had to brake suddenly. About 3 miles later noticed a drop in performance and car acting sluggishly. Will investigate all round tomorrow and see what I can find.

p.s. Is there a set of brake service seals that you can buy from dimmers etc?

 

[chrishawley]

On 17/06/2023 at 14:01, Martin White said:

p.s. Is there a set of brake service seals that you can buy from dimmers etc?

Service items readily available (Rimmers, Fitchetts, BiggRed, Paddocks for example). May be £15 or so for a set of piston seals and dust covers.

But a question might be whether to replace the pistons themselves as a part of the job (but then more like £40 per caliper). The common scenario is that the chrome breaks down on the inner egde of the piston and it's this corrosion which causes seizure. A good situation is when (with the piston seal not yet fitted) the piston with drop nicely into the bore under gravity and go to the bottow with a satisfying 'doink'. If it doesn't there's a need for further scrutiny.