Hi all,

Not the best first post to have but I guess sometimes this is just the way it works out. I've recently purchased a 53 plate WRX which has been great although was losing coolant due to a crack in the radiator. Replaced the radiator today and fitted new silicone hoses at the same time. Took it for a spin and car warms up great and stays at a good temp, however on hard acceleration the brakes seem to have developed a problem. They go very firm, similar to how a brake pedal feels when the engines off. Only lasts a split second but enough to be a bit nerve racking. Now I'm no mechanic so don't know how it could be linked but it didn't do it before the hoses were changed. I've checked and everything looks attached. Any ideas?

(Apologies if this has been discussed before, I haven't had a chance to search the forum as I'm currently on the hard shoulder of the A5!)

Thanks in advance.

 

After a bit of Internet digging, it is identical to this:

http://www.wrxtuners.com/forums/f72/my-brakes-lock-up-after-accelerating-29062/#/forumsite/20892/topics/29062

 

[QUOTE=Rob988;11607323]After a bit of Internet digging, it is identical to this:

http://www.wrxtuners.com/forums/f72/my-brakes-lock-up-after-accelerating-29062/#/forumsite/20892/topics/29062[/QUOTE
Never knew that! Let us know if there solution fixed it

 

One of the hose's you have swapped has a valve inside that is one way I think and this could be the reason ,,, its the one that is on the passengers side of the manifold and goes back to the bulkhead and along to the brake servo

I had the same problem and it was the hose I swapped to the brake servo

 

Is it transferable or did you swap it back? I assume it's not.

 

Right got home and found the hose I took off. Blew into it and the valves working a treat. No valve at all in the new hose so swapped it back.

 

Did same a few years ago. Rather than developing a Vacuum the turbo pressurises the servo so no brake assistance. SCARY at first.

 

Did you change it back or leave it?

 

Sticky in Technical I think.

 

I swapped it back to the original one

 

they can be a pain to remove but can be swapped...........

 

guess that's what I have done

 

Yep, done this a few years ago when I swapped the standard for some samcos. Got to the bottom of the street, went to brake and nearly crashed into a house. Properly s**t me up.

I recommend getting a VERY small amount of fairly liquid inside the hose and around the valve, then work it in. Worked for me.

 

+1

 

I had something similar to this a while back while "playing" in the snow, the brake pedal was rock solid when i went to press it an then went back to normal after like a second of brown pants scary time . I was thinking it might of been something to do with the centre diff locking because of spinning the wheels on the snow.

 

Same as what happens when you left foot brake, you loose servo assist. I'm sure we have all left foot braked and experienced this at some point

 

yeah I have changed my hoses over .how do you get the valve out of the old one.

 

Cut it out.

 

Most cars have one way valves in-line to the servo, so you can always get one out of salvage yard if you don't want to mess up a perfectly good hose.

Also make sure these so called "silicone hose" you've used for the servo is designed and properly re-inforced for vacuum. Its one thing to have a inlet hose collapse - you just lose power and its rare as they don't see manifold vacuum...but a servo vacuum hose does run at manifold vacuum and that collapsing can give you no servo assitance in just the same way as if you had no one-way valve, but much more randomly and when you least expect it!