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sprinkles08, ASE Certified Technician
Category: UK Car
Satisfied Customers: 22371
Experience:  ASE Master and Advanced level certified. Factory trained with 15 years dealership experience
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Am trying to find out the name of a valve I need to replace

Customer Question

Am trying to find out the name of a valve I need to replace on my 307. The brakes go stiff in the morning, servo has been changed and all the pipes are good no holes or leaks anywhere. Thinking it's the one way valve but don't know the name of it to buy a new one....
Can you help?
Submitted: 1 year ago.
Category: UK Car
Expert:  sprinkles08 replied 1 year ago.

Hello and welcome to JustAnswer!

It sounds like you're describing the brake booster vacuum check valve. A check valve is a valve that only allows flow in one direction and this is the only check valve in the brake system. It's remotely possible that the check valve is causing a loss of vacuum to the brake booster and causing the hard brake pedal but it's not that likely. The brake booster itself would be a more likely cause.

What you would need to do is check for prper vacuum at the booster at the time the pedal is hard. If vacuum is ok then the booster can be condemned. If you hear a hissing from under the dash when pressing the peal that's another sure sign of a failed booster.