Rear End Swapping Questions - 7.5 to 8.8

[old lx]

Well, so far my son and I have upgraded the ’85 GT with a 4-row radiator (which I already had on a shelf in the garage), a Performer intake manifold, and a 180-degree thermostat. We have also set the timing to 12 degrees BTC, and opened up the air filter canister by using a 14” open-element air cleaner top (which I already had on a shelf in the garage) over the 13” stock filter element to bolt the whole thing down. Yeah, I know that we’ll get some hot air in the mix that way, but we think the setup will be able to breathe better, and that the added breathing will be more of a plus that the warmer air will be a minus to the car’s performance.

Tomorrow, however, we’ll be kicking off the project where we swap out the 7.5 rear end with 2.73 gears for a rebuilt 8.8 rear end with 3.73 gears, and I have a few questions about how to do this. Although I’ve swapped out a rear end in a leaf-spring car before, I’ve never done it in a 4-link setup like the Fox-body Mustangs use.

In my mind’s eye, the proper sequence of events to remove the 7.5 after getting the car up in the air on jacks is to drop the driveshaft, then disconnect the e-brake cables, then disconnect the hydraulic brake line, then insert trolley jack #1 under the pumpkin, then disconnect the rear shocks. OK, now I have the upper and lower control arms to deal with, and the rear springs. I’d guess the best way to proceed would be to put trolley jack #2 under the lower control arms at the axle (one at a time), loosen and remove the lower control arm axle bolt and slowly lower trolley jack #2 until there is no more tension on the rear spring on that lower arm, then remove the spring. After doing both lower arms this way, there’s disconnecting the upper control arms at the axle, then lowering the rear end on trolley jack #1 and dragging the 7.5 out from under the car.

That’s how I think we’ll approach the task, but anyone with any corrections to my thought-process, or better ways to proceed, or handy tips you might want to pass along, please post them. I’m open to better ways to build the mouse-trap. Also, will the rear-end be inclined to try to rotate when suspended by only the upper control arms, or will the trolley jack under the pumpkin keep that from being a problem?

As you can all see, I’ll be having fun tomorrow. And for anyone who is willing to lend me any of their insight on this task, or point out any of its potential pitfalls, thanks in advance.

[fordfreak300]

I think you have it all under control. That's essentially how mine went.

[Evil86lx]

Rear swaybar.. :D

Rmove the sway bar, remove the shocks, you should be able to lower the rear end far enough to pull the springs. Remove the contol arms. If done this way only one jack is needed.

kyle

[old lx]

Oops, yes, rear sway bar. It'll come off early, maybe even before I drop the driveshaft. And, now that I think about it some more, I'll also remove the kicker shocks before I remove the main shocks

About being able to pull out the rear springs at full droop, the experience I've had with that is "sometimes yes, sometimes no". But I'll certainly try it, and I'll do it that way if I can.

Thanks.

[Evil86lx]

:D

We rednecks alway's seem to find the cheap/easy way to cheat things.
Must be in the blood.. :lol:

kyle

[fordfreak300]

I forgot about the sway bar, might be because I don't have one on my car. Well it will have one very soon I should say.

[mikejb]

The one thing I regret doin on my 7.5 to 8.8 on the 82 I kept the stock lower control arms. I swapped in a set of UPR's later on but I wish I woulda done it on the rear swap.

I would rec at least doin the lowers. Timt and $ permit do upper and lower.

[Evil86lx]

The one thing I regret doin on my 7.5 to 8.8 on the 82 I kept the stock lower control arms. I swapped in a set of UPR's later on but I wish I woulda done it on the rear swap.

I would rec at least doin the lowers. Timt and $ permit do upper and lower.

Good idea.. Thats what i did, upper's and lowers at the same time as my rear end swap.

kyle

[fordfreak300]

I wish i would havre done that. i still have yet to replace either set.

[Kevins89notch5.0]

Don't snap the brake line like I did! :(

[82boy]

a little trick to make it go better. disconect the sway bar shocks brake line and drive shaft. now let the rear end fall to the full extention of the suspention. now take the jack to the pass side and jack up on the end of the rear end till it will not move anymore without moving the other side. now go to the drives side push down on the rear end and pull the spring out. now lower the jack on the pass side and put the jack on the drivers side and repeat. now you can just disconect the control arms. also when reinstalling the rear end just do it in reverse. bolt the control arms up using the jack put the springs back in, and so one. just be carfull with it all and especialy with the springs they are dangurous.

[Dugzy33]

Just completed a 7.5 to 8.8 swap.

Springs will come out without a problem. They wont even have any "spring" left in 'em. Just let the suspension down after shocks are gone and they will pull right out.

Brake line issue...


My brake line was on the pass side.
8.8 is on the right.
All you need is a chunk of 3/8 brake line with fittings attatched.(get this at just about any parts store)
Connect to the pass side existing. then bend up into the tunnel and over to the driver side.

Get the brake line bracket( from the 8.8 donor car) that is attatched to the body. I just pryed on the rivets that hold it to the body till it came off, and then used sheetmetal screws to attacht to the same spot on my car.
Also get the fitting off the 8.8 car. You will need this to attatch the 8.8 flexible hose from the rear.

I hope you can understand this! lol
I am sure there are other ways to do the brake line, but I prefer to stick with the stock components if possible so I can get them easily if I ever need to replace them.

Let me know if you need any pictures. I could crawl under the rear and snap a few if you need.

Good luck.

[old lx]

OK, it's in, and everything seems to be fine. So thanks to everyone for their input.

The hardest part of the whole project, aside from becoming re-acquainted with just how hard my concrete garage floor can be after awhile, was connecting the hydraulics. The original 7.5 rear and the new 8.8 rear had entirely different setups for the hydraulic soft line. But we persevered, and with a bit of bracket-cobbling and a newly-purchased 7/16" flare wrench, we made everything work.

So we've driven the car now, and there's no doubt that 3.73's are better than 2.73's. I know that's not exactly a revolutionary idea, but it sure is true.

From the test rides we've taken, however, I've come up with some more questions about the carbuteted 5-liters, which I will post soon as a separate thread on the board.

[fordfreak300]

Glad to hear you got everything in.

[Cappn Tripps]

I just used the brakes off the 7.5... guess I was lucky.. everything bolted right up, hung the brakes with wire and the block was on the same side..
FWIW, the vent unscrews so you dont even have to take the brake lines off

:lol:

[Dugzy33]

I just used the brakes off the 7.5... guess I was lucky.. everything bolted right up, hung the brakes with wire and the block was on the same side..
FWIW, the vent unscrews so you dont even have to take the brake lines off

:lol:


???? What do you mean?
The "brakes" are the same. The only difference is the location of the hard line and soft line. And the fitting that connects the hard to soft line.


7.5 both are on pass side.
8.8 both are on driv side.

How did you"keep" the 7.5 brakes?
You have to get the emergency brake cables out of the backing plates.
I guess you could take the backing plates off, but then you would have to remove the axles!!!
Seems harder that way.

Easy way is to run small lenght of hard line to ither side of tunnel and hook it up there to the 8.8.
Sounds like what most do.
Anyway that is the way ford did it on the 8.8's

If you have any pics of what you did send em to me...
I still have 3 fox chassis caes to do the swap on.
So I am always looking for any easy way to get the job done.
Thanks


Hey old lx did you hook up the quad shocks?
If not are you getting axle hop?
My tires are too wide for the quads, but now I get hella axle hop.
I think I will try new lowers as I have heard that that will cure the problem.
What do you think?
Thanks

[Cappn Tripps]

nope, all the lines were the same on mine.. the soft line runs to the block that is held down by the rear end vent.. the vent comes out.. I unbolted the brakes with the lines attached as well as the vent. Put the rearend in and dropped the brakes back down, put the vent and block on the 8.8 and was done

only thing I didnt use was the retainer clip on the back cover.. no biggie..
and I did pull the axles.. easier in the end and you might as well change the gear oil, that way you know it's fresh.. and the block and vent were on the passenger side on the 8.8 I got.. out of an SN95.. I couldnt use the 5 lug axles anyway, so I had to swap 'em

http://members.cox.net/cappntripps31/Image006s.jpg

[old lx]

Dugzy33,

Yes, I hooked up the quad shocks. And I reversed them, putting the body of the quads closer to the axle. That provides a bit more tire clearance.

How wide are your tires? We're running 265-50-15's on the stock 10-holes with no interference.

My experience with removing quad shocks (which may be different from the experience of others) is that I didn't get as good traction with them removed as I got with them installed. This was on my '88 fuelie automatic, with Southside lowers.

On the 8.8 I installed, the junction block between the soft brake line and the hard brake lines was on a bracket that attached to the driver's side of the differential, and reached up from there to position the block itself above the driver's side of the differential, in roughly the same position as the the location of that same junction block on the 7.5 I removed. On my 8,8, the junction block was in no way associated with the vent, which is located in the top of the passenger-side axle tube.

[Cappn Tripps]

if you look at the pic, the junction block is on the passenger side.. the thing that holds it to the housing is the vent .. at least on mine....

[old lx]

Yes, I can see that on your 8.8 rear-end, the junction block's location is different than where the junction block was located on my 8.8 rear-end.

It looks as if Ford has taken more than one cut at figuring out where and how they want to locate the junction block on 8.8 rear-ends.