influence

1991 Fox 5.0

The brakes worked fine before I did the following:

I recently upgraded my brake set up to the PBR Cobra Brake Kit with 13" Brmbo Rotors, and I believe it was 10.5 on the back. I flushed the brake lines and bled the brakes. There are no leaks in the lines or on the vacuum junction box to manifold and brake booster.

Now the Brakes are hard as a rock, the car stops, but you really have to press on the brakes, very hard.

Does anyone know the problem/cure?

Thanks in advance,

Scott

campbellsoup24

Didyou changed your Booster and Master Cylinder when you changed your brakes?
I am doing a 5-lug conversion w/t bigger brakes and have to change all that stuff.
http://www.mustangmotorsport.com/frontbrakes.html
Try going to that sight, they have everything you need to know about what to do.
Sounds like you need to upgrade that stuff to, if you do you can go with a 93 Cobra MC and booster, that will match right up to your other brake booster, you may also have to go with a 3-2 conversion kit.
I am currently looking for a place that has those.
Hope that helps alittle?

influence

Thanks for the input. I wonder if the brake booster cannot handle the bigger brakes? I will check that out.

Well I have the wilwood porportioning valve on there as well as the 3-2 and the cobra master cylinder. I am not sure if the brake booster was changed over.

Also if you go to http://www.fordracingparts.com/downl...tionsheets.asp There is an instruction sheet as well.

The problem is all I did was just add the cobra brakes, SS Lines and rotors. After I bled the brakes this happened. I wonder if it is the brake booster.

Thanks,

Scott

campbellsoup24

Yeah I think you need to go with the bigger booster. Thats what it says on that web sight.
Do you have a bigger cam in you car? That can also do it (or so I have been told) They don't creat enough boost and you may have to go with a vaccum booster. I am going to try that ifI have a problem with mine when I get it all finished.
I have just been reading up on all this stuff the past few days just to make sureI get all the right stuff to do mine.

influence

Mild E303 Cam.

You say the 93 Cobra Brake Booster will work? Is this without any mods to it? In the Ford Racing Directions it says you need to modify the Brake Booster. Just wondering if there is any difference.

Also by the way that link doesnt work you gave me.

Thanks and good luck with your project

campbellsoup24

According to what it says in the link the 93 Cobra will fit right inplace of a stock 5.0 fox. If you go with a newer one than it needs to be modified, the holes don't line up. I have a E303 cam in mine as well and when I started driving after I had it put in the brakes were hard for me too. Thats whenI found outI may need a vaccum booster. I just figured since I was doing a 5-lug conversion I would try this rout first and see if that fixes it, if not I will probably go with a vaccum booster.
Try typing that site in?

90Lxstanger

Isnt the LSA on the E-303 lower then stock(116 i believe) which means vac. is lower resulting in loss of power brakes, wheni was doin my pcv vavle i didnt have one of the hoses and ran my car 1 day with the B/B hose undone, it sucked.

influence

Well since ford discontinued the PBB for the 93 cobra, I found one for 139.00 with tax and I get 34.50 back when I bring in my stock booster. I have been bleeding the lines and actually flushed them with an automatic brake bleeder, much easier. and the brake is getting better I also found a few small leaks in the lines, i mean tiny, so I tightened those up and going to now bleed it again. I will let you know what happens.

Thanks

campbellsoup24

I just put a rebuilt cobra booster in today and it was a pain in the ***! I had to bend the corner of the booster to get it past my strut housing! I hope that I didn't screw it up to bad? It still seems to work fine, but the bolts are alittle bent for the MC so I will have to see if it will go on ok? I should have it in a few days? Let me know if you have the same problem, if not, let me know what works for you incase I have to put in another one? The bolts lined up good though once I beat the crap out if it!

Thanks.