I have a question regarding an 8" rear axle I bought for my Pinto many years ago. I am highly considering installing it in my car before Carlisle & am wondering what work I should do to it before installing it.
I have new studs, as the old ones were broken & I know the gaskets, but what else should I do? I am going to use my current brakes but didn't know what I should check on it to make sure it's still good.
It has sat outside for atleast 3-4 years in the elements, so I wanna make sure it's still okay to use.
Hello,
I assume you are coming from the perspective of having a 6-3/4" already. I need to caution you that the drums for the 6-3/4" are different than the 8". The center hole is the wrong size. I don't know about the backing plates, shoes etc.. When I got my 8" at Pick A Part I spent the extra $10 and got it "drum to drum." I'm about as cheap as they come, but I never regretted the cost.
As to the rest, I would assume that as long as water never went over the vent opening that things inside should be OK. What is the ratio? I think 3.25 is just about the best (but I have a 2.3 Turbo/T-5). I was told that 3.25 is very rare (from the factory) and as a junk yard item difficult to find. Most come with 3.00 or 3.55. 3.40 is a possibility and I think the best compromise.
Tom
Thanks for the info Tom! I lucked out & still have the drums that came from the axle, so I will get them checked & see if they can be turned to clean them up. The shoes & hardware were all shot so I was planning on using the brakes & hardware that are currently on the car now. They only have about 1500 to 2000 miles on them, so I can still use them.
I'm not sure of the gear ratio, as the tag is long gone on the axle itself. I bought it off ebay for $25.00 in Dayton. I couldn't believe the cost but never checked on the radio. Is the best way to find out the ratio to count the teeth on the pinion gear, compared to the ring gear? I know the carrier gasket will need replacing so I will be changing that. Not sure of the rest though.
Since the rear is out of the car, the easy way to check the axle ratio is to mark the drum or axle flange with a dot of whiteout or a piece of tape then turn the diff yoke so that the drum/flange turns once. Count the turns of the yoke. 3 turns of the yoke is a 3.00 ratio (90% chance of this factory ratio). If it turns 3.4 turns to one revolution of the drum/flange, it's 3.40 ratio, etc...
71HANTO
ok thanks, I will do that when I am at the car next. The axle is in front of the garage, so that shouldn't be too difficult
One more quick test...if you turn the drum/flange on one side and the other side turns in the same direction, you hit the jackpot and got a posi (limited slip) rear end (99% chance of not). If the other wheel turns the opposite way, you have a standard one legger.
71HANTO
Like I said I'm not sure if the backing plates etc. transfer over. One possible indicator might be if the shoes are listed the same for a 6-3/4" and an 8". When I sent my donor '88 Turbo Coupe off to be scraped I pulled the 3.55 Posi 8.8" and literally welded in the 6-3/4" in just so it could be rolled away on 13" tires (see image). Sold the 8.8" for $100 so it was worth the 30 minutes to do.
Hope you get it all sorted out.
Tom
nothing from the 6-3/4 will work on the 8" :P it's a pretty easy swap but you will need everything for an 8"
>>>nothing from the 6-3/4 will work on the 8"<<<
That was my concern for this guy. I knew the drums didn't work. As I recall the shock mounts are different too if they were from a Mustang II. Not that the Pinto mounts won't work, but it would be a hassle to put on the wrong ones and then have to take them off.
Not mentioned yet is the driveshaft length. I hope he knows to be aware that it is likely different. I'm not sure of all the combination's, but I went from a C-4 / 6-3/4" to a T-5 / 8" and the shaft fit perfectly! I think there is a different shaft needed with just the rear change??? Hopefully someone with more experience here can advise him.
If there is any good news the Pinto brake cable fits.
Tom
When I put the 8" in mine I still had the 2.0 4 speed. IIRC the Pinto shock mounts fit but I had to drill the holes out for the bigger u-bolts. The driveshaft will be up in the tailshaft 1" further, didn't cause me any problems.
My 8" came from an early Mustang II ('74) which were 3:55 rears. The later MII's were 3:00. The 3:55 seems to work well with the T-5. Still have to put a tach on it to see the real rpms at cruise.