Brakes The Ultimate 4-lug/5-lug Brake Conversion/upgrade Thread

  • Sponsors (?)


Help! I don't think I saw in here what I needed.

I have a 99 3.8 car with a 7.5 rear end.
I purchased a 4 lug 8.8 rear end. We bolted the housing into the car and put my 99 axles in but the caliper is not bolting to the bracket correctly. (I guess this is what I'm seeing referred to as wrong track?)
I'm near broke but I can buy brackets if I need to.
Would prefer not to have to do any cutting/welding.
Someone please give me some options here to make what I have work.
Still have everything from my 7.5 and everything from the 4 lug 8.8.
 
Help! I don't think I saw in here what I needed.

I have a 99 3.8 car with a 7.5 rear end.
I purchased a 4 lug 8.8 rear end. We bolted the housing into the car and put my 99 axles in but the caliper is not bolting to the bracket correctly. (I guess this is what I'm seeing referred to as wrong track?)
I'm near broke but I can buy brackets if I need to.
Would prefer not to have to do any cutting/welding.
Someone please give me some options here to make what I have work.
Still have everything from my 7.5 and everything from the 4 lug 8.8.

I suggest you measure the length of the 99 axles vs. the axles from the 7.5 or 8.8 rear end.
 
That's the problem. My 99 axles were too long. Someone had told me everything would bolt up and interchange to get me where I need to be. Another source tells me that if I use the fox 8.8 housing, 94-98 axles with my 99 brakes it will work.
 
That's the problem. My 99 axles were too long. Someone had told me everything would bolt up and interchange to get me where I need to be. Another source tells me that if I use the fox 8.8 housing, 94-98 axles with my 99 brakes it will work.


Correct. The rear brakes of the 99-04 V6 and GT is identical to the 94-98 GT and v6 other than the axles. The 99+ axles are wider.

Just get a set of 94-98 axles.
 
Hi gang. Long time listener, first time caller.

I've been reading and researching brake upgrades for my 93 fox for several months and based on Mike's great info (thanks btw!) this is the setup I went with...

93 Cobra MC
93 Cobra booster
99+ GT/V6 PBR fronts
94+ SN95 rears

It's my understanding that this is basically the same ratio/setup as the 99+ V6 as the 93 Cobra MC and the 99+ V6 MC are both 1" bores.

My problem is, my pedal is too soft and travels too far. The braking power is also underwhelming. I checked the booster to MC pushrod length. I double checked all my fittings/connections, no leaks. I bench bled the MC before install and bled the brakes. All my hoses are steel. Is there anything I'm missing?

I'm going to re-bleed the brakes this weekend just to make sure since the entire system ran dry during the conversion. Could it be something as simple as air in the system or should I consider going to the 1 1/16" bore MCs?

Thanks.
 
  • Like
Reactions: 1 user
Something is a-miss. @NightFury I have the same setup and it is absolutely amazing stopping!

Is the MC new? What about the boosters? If calipers sit around the Pistons may be seized?

Booster is a Dorman(?) rebuild. Master cylinder is new. Calipers are used but there was no unusual resistance when I reset the Pistons. Seals and slides are in good shape and lubricated. The only thing I'm not 100% about was whether or not I got all the air out. I only used about 3/4 of a quart. Is that about normal for a full system flush?