This is topic HELP! Car won't brake after 5 lug swap in forum Tech Talk at Northern California Ford Owners  .


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Posted by Fast92lxcoupe (Member # 8221) on :
 
Hey guys. I did a 5 lug swap early this year and my car has just been sitting in the driveway because it doesn't stop. I did a 95 GT front set up and an SN95 rear end. I also out in a proportioning valve on the passenger side (under the hood by the firewall). However, I didn't change my booster or master cylinder. Any idea what my problem may be? Is it my master or booster?
 
Posted by 5.0 LsX (Member # 10017) on :
 
put the 94-95 master on, problem solved
 
Posted by 5.0 LsX (Member # 10017) on :
 
o, it will require some modifications of the brake lines where the oem prop valve is
 
Posted by S351-R (Member # 1605) on :
 
quote:
Originally posted by Fast92lxcoupe:
I also out in a proportioning valve on the passenger side (under the hood by the firewall). However, I didn't change my booster or master cylinder. Any idea what my problem may be? Is it my master or booster?
So you now have two proportioning valves (the stock one and the aftermarket)? You only need one.
 
Posted by 68stanger (Member # 7842) on :
 
You need to gut the stock proportioning valve for use with rear disc brakes. the stock proportioning valve doesn't provide enough pressure for disc brakes and doesnt allow the pistons on disc brakes to back off the rotor (constant drag)
 
Posted by Fast92lxcoupe (Member # 8221) on :
 
quote:
Originally posted by 68stanger:
You need to gut the stock proportioning valve for use with rear disc brakes. the stock proportioning valve doesn't provide enough pressure for disc brakes and doesnt allow the pistons on disc brakes to back off the rotor (constant drag)
Already gutted the original proportioning valve.
 
Posted by Fast92lxcoupe (Member # 8221) on :
 
quote:
Originally posted by 5.0 LsX:
put the 94-95 master on, problem solved
So just the master? I wouldn't have to swap the booster?
 
Posted by Fast92lxcoupe (Member # 8221) on :
 
quote:
Originally posted by 5.0 LsX:
o, it will require some modifications of the brake lines where the oem prop valve is
And one more thing, I'm planning on buying the MM proportioning valve delete kit
 
Posted by 89foxstang (Member # 5908) on :
 
I think to make it easier to diagnose over the Internet it would help if we knew what exactly you mean by not braking, ex: very stiff pedal, very soft pedal, no pedal!! Lmk might be able to narrow the problem down a little better
 
Posted by Fast92lxcoupe (Member # 8221) on :
 
quote:
Originally posted by 89foxstang:
I think to make it easier to diagnose over the Internet it would help if we knew what exactly you mean by not braking, ex: very stiff pedal, very soft pedal, no pedal!! Lmk might be able to narrow the problem down a little better
Super soft pedal. I took the car up 20 mph and slammed on the brakes and it took about 40 feet to come to a complete stop. When the car is jacked up, and I let the rear wheels turn I can slam on the brakes and it'll take forever for the rear wheels to stop
 
Posted by Ryn621 (Member # 11276) on :
 
did you bleed the brakes to make sure all air is out
 
Posted by Fast92lxcoupe (Member # 8221) on :
 
quote:
Originally posted by Ryn621:
did you bleed the brakes to make sure all air is out
I bled the shit out of them
 
Posted by 89foxstang (Member # 5908) on :
 
Sounds like it could be a bad master, if you bled all the air out and the master was building pressure, I would assume you should have a stiff pedal... With that said an incorrect piston size could cause a mushy pedal, but I wouldn't think it would be that bad? When I did my cobra brake swap I swapped the master, and went with manual brake setup. I had a super stiff pedal lol
 
Posted by 89foxstang (Member # 5908) on :
 
Also I'm assuming you've played with the proportioning valve to see if it makes any difference? Are the fronts just as bad?
 
Posted by dohc90lx (Member # 11863) on :
 
if there is a bleeding port on the master bleed it too. there can be air cought in the master if you didnt bench bleed it.
 
Posted by stangin' (Member # 514) on :
 
you need to upgrade your master cylinder. i went with a 93 cobra MC and booster when i did my cobra brake setup. bench bleed it and your braking should improve dramatically.
 
Posted by 89Rodknocker (Member # 2951) on :
 
When u gutted the stock prop valve u put the plug in right? And you added an adjustable prop valve on the right side where the union is right. If not your never gonna get any brakes.

[ September 03, 2012, 07:52 PM: Message edited by: 89Rodknocker ]
 




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