Ford 8.8 build

[inVERt'D]

Seems like the vast majority of disc brake swaps I hear about (for Jeeps) never mention using an adjustable proportioning valve to dial it in. I kind of suspect this an area where off road enthusiasts are behind the performance technology curve, so to speak.

If it were me I'd get an adjustable proportioning valve from Summit or something. If I was to assume anything about the braking power of your new discs compared to your old drums, it's that they will have more stopping power. Maybe the your master cylinder's built-in proportioning is close enough to get you by in normal driving, but in a hard stop it could mean the difference between going sideways and staying straight.

[OU812]

The adjustable proportioning valve will only lesson braking force do the rear brakes. So if your setup is not applying enough braking in the rear it will not help. Its a tool to prevent the rears from locking up first in race cars.

[OU812]

Never mind Im sorry. I just realised you can put the prorortioning valve on the front brakes and restrict braking pressure till the rears lock up at the same time. I really don't have a problem with my brakes though. Its funny to see that the discs in the rear are a lot bigger than the fronts.

[Guest]

I forgot Scott, did you get the LSD or open? I was going to flush the fluid while I have it out and didn't know if I needed the additive or Royal Purple, AMSoil, or sythetic was fine?

[OU812]

I had the LSD but swaped to an open carrier in preperation for an Aussie. I used Redline because it has a friction modifier in it already. I think royal purple and amsoil do too.

[Guest]

Thanks Scott.

Another question

Which perch size do I order?
http://www.summitracing.com/search/?...=perches&dds=1

[Guest]

Ok. Took pic of my perch and the one from summit. 3" axle tube and 2.5" for the leaf springs. Look right? Or does anyone have a part number from Summit? I assume the reason for new perches is the 8.8 perches are 2 1/4" width and the D35 springs are 2 1/2"?

$12.95 for 5" length.
http://www.summitracing.com/search/?...perches&page=1





These are 7 3/4" longer to avoid axle wrap $28.99

[OU812]

Mostly new perches are needed because you have to move them a little. You could cut of the ford ones and mount them in the correct position if you can get a clean enough cut.

[Guest]

Plus the Ford is 2 1/4" and the left springs are 2.5" width. Less hassle to just buy them I assume.

Question would be then is it better to spend the $16 dollars to the the 7 3/4" length? It says you can adjust the axle WB and the longer perch avoids axle wrap. Snake oil or worth it?

[OU812]

I am just talking out my a$$ here but I don't think longer perches would help With axle wrap. I think that most of what is happening in axle wrap involves the top spring flexing. Especially if you have an over load spring. What is a wider base on the perch going to do for you to cure axle wrap that an overload spring doesn't?

[Materdaddy]

Never mind Im sorry. I just realised you can put the prorortioning valve on the front brakes and restrict braking pressure till the rears lock up at the same time. I really don't have a problem with my brakes though. Its funny to see that the discs in the rear are a lot bigger than the fronts.

You want the fronts to lock up first. The locked up tires will lead, so if you lock up the rears, you'll start going sideways.

[Guest]

I agree. But, I wasn't sure if it was snake oil or maybe it was true.

Now, what I don't have a clue on it the multiple mounting hole to position the axle. Worth it to move it back some. Or does that creat more problems? Or solve none. I would think more stable after but not sure.

Did you weld your axle tubes?

[Guest]

You want the fronts to lock up first. The locked up tires will lead, so if you lock up the rears, you'll start going sideways.

So, no valve is better (or needed). Am I understanding you right?

[OU812]

You want the fronts to lock up first. The locked up tires will lead, so if you lock up the rears, you'll start going sideways.

The point of proportioning valves is not to make the front lock up first but to balance the front and rear so the rears will lock up soon after. Locking up the tires is almost never a good option (two feet in to spin) but you do want to get the most out of your rear brakes.

[2blk2drs]

I used a ZJ proportioning valve when I did my ZJ disc brake swap.

Upon swapping in the 8.8 I found that the caliper mounting brackets are nearly identical, and the part numbers cast in were only a few off. This might be a good place to start.


On the rear perches: the 8.8 tubes are 3.25" so the 3" perches will work. The longer perches could help with axle wrap. When my leaves went south they turned into a W shape right at the perches. The extra holes would come in handy later for stretching the rear, which may help your tires stuff better.
May as well weld the tubes since the axle is out, and you are welding stuff already. 1/8 7018 worked well for me.

GL! :beer: