Smart Fortwo - front brakes both seized

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Thu 2 Feb 2012 08:54
Smart Fortwo - front brakes both seized - speedyxjs

What would cause both front brakes to seize when the engine is running? If i open thebleed nipple to release the pressure, the wheel frees up but without the bleed nipple open, the pistons wont push in. I thought it might be te servo but the rear wheels are fine which is really odd at as i beleive these cars operate a dual line braking system. Does anyone have any idea's where to look next?

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Thu 2 Feb 2012 18:42
Smart Fortwo - front brakes both seized - gordonbennet

First things first, have you stripped the brakes down, cleaned and lubricated the sliding parts (i assume they are single piston calipers) of the front calipers, with recent heavy salting its just possible they have seized solid.

That would be my first job before looking for more involved issues.

Why do you mention 'with engine running'?, does this not happen if you apply the brakes hard (well as hard as you can without vacuum) without the servo, how does this manifest itself?

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Fri 3 Feb 2012 13:21
Smart Fortwo - front brakes both seized - Cris_on_the_gas

Might be that parking brake operates on front disc brakes in which case might be a ratchet mechanism for this which is stopping the pistons pushing back in.

Just a bit worried that you tried to free up by using the bleed nipple, this should never be necessary. Just be creful as brakes as you can appreciate are mission critical and you should not work on them unless you feel confident

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Sat 4 Feb 2012 13:07
Smart Fortwo - front brakes both seized - Peter D

Remove the vacuum pipe off the servo and run the engine. If tha tis not the cuase then I suspec the ABS pump is running/faulty. Regards Peter

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Wed 15 Feb 2012 13:53
Smart Fortwo - front brakes both seized - speedyxjs

Thanks for the replys, turned out to be the master cylinder was faulty. Took 5 days to get here from germany!!

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Wed 15 Feb 2012 15:19
Smart Fortwo - front brakes both seized - Peter D

That's why I asked you to "Remove the vacuum pipe off the servo and run the engine.". Glad you've fixed it. Regards Peter

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