brake issues running a breather?

[88-378]

Hey all, just like the title says.

I am running both a pcv valve and a breather and have a really hard pedal and no brakes. I am thinking that the breather is causing a vacuum leak which will not operate the booster. Plus I have an auxillary vacuum canister due to my cam.

The only thing i have found is that the breather will cause vacuum issues, but that much to create booster problems?

 

[Mustang5L5]

What's your vacuum readings? Hook a gauge up and see what you are pulling.

Also, do you have a booster leak? There is a 1-way valve on the booster that allows the booster to "charge" with vacuum and not lose it when the level drops, say at WOT or under boost. If it fails, you basically have no assist.

Could be a gross booster failure as well

 

[Rick 91GT]

Usually the open breather will not cause brake issues...

 

[88-378]

I am going to go thru everything again. I would still like to run the breather if possible.

I changed over to dot 5 when i replaced the brake system. I may still have a little dot 4 in it, but i doubt it. I flushed two quarts of dot 5 thru it.

I am going to take some vacuum readings and also check the pressure at the calipers.

 

[Mustang5L5]

I just remembered I ran a breather on my car for some time...no brake issues at all.

First thing I'd do is get a vacuum reading, and then test to see if the booster is holding vacuum. Have you changed anything before the problem started?

I'm gonna assume ypu know about the potential issues with running DOT5?

 

[Rick 91GT]

I've had some cars not like a open breather and cause lean pops out the intake track but never an issue with brakes.

I've had a couple customer cars leak through the booster however.

 

[88-378]

Thanks guys. i'll figure it out.

5l5, yeah I heard the whole dot 5 debate. If i listened to every debate/opinion/story/experience/etc.. I would never work on my own car.

run this, don't run that, this works, that doesn't....it drives me crazy!

 

[88-378]

Well, looks like a vacuum leak somewhere. i am only pulling 10-12 inches at idle.

Checked at the tree and fuel pressure reg.

 

[Mustang5L5]

Is the low vac a result of the cam? Or a leak?

I'm not familiar with that camshaft and the amount of vacuum it should pull.

 

[88-378]

No idea. But i do have a reserve canister for the brakes. I deleted all emissions and EGR, etc...

Who knows, I'll keep looking.

 

[88-378]

Checked for leaks, so far can't find anything.

this sucks. car is ready to go too!

 

[Mustang5L5]

Is this the first time running with that cam? Your low vac issue might be camshaft related and not a leak

 

[88-378]

nah...I had in before and the brakes were fine. I don't know what the story is.

I hate to do it, but i am going to have to take her in to the shop.

 

[88-378]

I think i have found a solution. seems others have had this problem from working off of Saleen/SVO/Lincoln brakes.

I am going to put in a 94/95 Cobra mc. Should help...I will keep you posted.

 

[88-378]

5L5, i read your article on this issue in the sn95 tech section when i google searched power brake booster. I guess someone was wanting run one. Anyway, it confirms my research using the cobra mc. getting those lines, apv and stock pv delete kit from mm tomorrow.

 

[shootshescores]

I just had a new heads, cam, & intake package finished and the cam is dropping my vacuum enough to where the boosting isn't providing much assist. I'm not real happy with this and was wondering if you have had any luck with your set-up since the last post?

 

[Mustang5L5]

5L5, i read your article on this issue in the sn95 tech section when i google searched power brake booster. I guess someone was wanting run one. Anyway, it confirms my research using the cobra mc. getting those lines, apv and stock pv delete kit from mm tomorrow.

What did I say?


I'm sorry...i get PM's and emails about so much brake stuff I lose track of what I told whom.

 

[shootshescores]

The cam is an Anderson Motorsports N-412. It's a mild cam similar to something between the E303 & B303. I have also elimated the EGR and added a valve cover breather. Also, my car has a SSBC rear disc conversion kit with an SVO MC. The kit doesn't inclue a proportioning valve so it doesn't have one, but I've never had any problems. I spoke with Anderson Motorsports Tech on the phone this morning (since its their cam) and they said that they have never seen vacuum trouble with this mild of a cam. The shop has a long reputation as the best shop in the Detroit area specializing in Mustang Performance. Do you think its my new combo, the shop created a vacuum leak during the job, the guy just isn't use to how my car feels braking, or something else?