My car just failed it SVA on brakes. The front OSF wheel locked up fine on the rollers but the other wouldn't perform well enough to pass. Any ideas on a cause or solution? They're Sierra calipers and a Sierra MC.

Are they all new bits? Or is there some air in the system?

Sticking caliper/pad? Clean and lubricate(coppaslip)the pad and the caliper slider after making sure the pistons are free.

Front calipers were won on Ebay for £2.50 I'll try giving them a grease up. Ta. My heads a bit all over the place at the moment.

£ 2.50 eh1?!??!?

still, doesn't implly they shouldn't work.

were they overhauled?

a good clean, check the pistons and fitting seal kit would see them ok. aslo blow through with air line incase some crap is stuck in the drillings.

It was more £2.50 because he didn't put a reserve on them and I did in all honesty feel bad for taking them off him for that price, all sprayed up as well but such is. regardless like you say a strip down is probably in order.
Any ideas as to how I can effectively test them to SVA standards once they're done?

quote:

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Originally posted by mistergrumpy
It was more £2.50 because he didn't put a reserve on them and I did in all honesty feel bad for taking them off him for that price, all sprayed up as well but such is. regardless like you say a strip down is probably in order.
Any ideas as to how I can effectively test them to SVA standards once they're done?

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The caliper is knackered end of story get a service exchange.

If the pads had been sticking you would have noticed it when you fitted the pads.

Don't put grease, Coppaslip, mineral oil or WD40 anywhere near the ruber compents or surfacs that come into contact with the rubber components as even the tinyest trace will eventually destroy the elasticity of the seals.

The only safe lubricant to use near rubber brake components is Lucas-Girling Red Rubber Grease also sold by Castrol.

Coppaslip or alternatively White High Temperature Brake grease can be used on the edges of the pads caliper guides and anti-squeal shims but must not get anywhere near the seals.

Why do you say the caliper is knackered? Based upon what? I ask because only the front offside locked so surely you're not saying the other 3 are knackered too.
Just because I got them for £2.50 doesn't necessarliy mean they're crap. They were taken off a Tiger after an upgrade.

Caliper is knackered one (or both) of the piston are seized fully back in the caliper a very common problm with M16 calipers.

Easy enough to check --- just remove one pad at a time then give the pedal a tiny pump to about 1/3 of the pedal travel, the piston should move out and stay out untill it is pushed back.

Didn't know Sierra's had M16 calipers.

Nah I thought M16 were Cortina. Anyhow I've just had the f/n/s caliper off and it works fine and retracts. The pads are still incredibly square and new though, being as how they haven't been used and all. I'm thinking that this may be the problem. Going to have another play tomorrow.