Just remembered I had this kit for the UCA bushings. Worked great!!!
8.5 in rearend
- Thread starter Billy1979malibu
- Start date
Just catching up on this thread.
Your rotational torque is low because the bearings are whipped. Which isn’t a problem for a daily driver, but they wouldve been exposed (haha) if you didn’t rebuild it.
Be advised, the torque required start the rotation will be much greater than what it takes to keep it rotating.
You need to be measuring the rotational torque, not the breakaway. And it’s measured with the axles and pinion seal removed. I’d recommend a fish scale, a torque wrench designed to measure rotational torque or an experienced person with rear end rebuilds.
Also, with new bearings and gears it will seem too tight when setting up.
Your rotational torque is low because the bearings are whipped. Which isn’t a problem for a daily driver, but they wouldve been exposed (haha) if you didn’t rebuild it.
Be advised, the torque required start the rotation will be much greater than what it takes to keep it rotating.
You need to be measuring the rotational torque, not the breakaway. And it’s measured with the axles and pinion seal removed. I’d recommend a fish scale, a torque wrench designed to measure rotational torque or an experienced person with rear end rebuilds.
Also, with new bearings and gears it will seem too tight when setting up.
Could you explain what you mean by, "it will seem too tight when setting up"?
I was kind of hoping to become one of these people 'experienced with rear end rebuilds'. I'm sure there's a lot of nuance and experience to gain but, it should be within my grasp with the proper tools.
I guess I could put a fish scale on my torque wrench and divide by the inches from pivot..
I'm going to get this right one way or another. I'm not putting it in the car unless I'm sure it's good.
That is a Trutrac with 3.42 ring/pinion, not an elocker. I'm replacing the 3.73 open that came with 442 donor car. Looking to drop a few highway RPM.
Last edited:
My friend Robert at the transmission shop who built the 7.5" LSD in car now, my 4l60e and the 6-speed in my minivan says that I'm probably going to be close to dead nuts using the factory iron shims with the new ring, pinion and carrier... we'll see. He's going to take the bearing off the pinion for me tonight. I've done so much business with him over the years that he's available for advice and small things like pressing a bearing. He was talking to me about eyeballing backlash and rotational torque. I was telling him I'm just going to use the numbers in the book. He said 'good man'.
I'm also just now catching up on this thread. Others such as Clone Tie Pilot, GNVAIR, and RT Jam have mentioned the Ford Crown Vic rear and coincidentally I've been reading up on it lately. Another member, tokarz1 did a real nice job setting his up.
I was looking at using a shortened P71 Crown Vic aluminum driveshaft in conjunction with a B Body differential, as I'm considering using that instead of an 8.8 from a Fox Body Mustang. That reading led me to a few people actually using the whole Crown Vic diff (up until '97) and upgrading the guts, and one of those people is tokarz1. Apparently the Vic's UCA ears are in almost identical positions as the G Body (Mustang isn't), the lowers are also very close, the spring perches are off by 1/2", and the rears are fairly cheap and plentiful since they're in multiple cars. They're a bit wide and need shortened, and it seems that using UCA for a 73-77 A Body would be beneficial.
www.montecarloss.com
I was looking at using a shortened P71 Crown Vic aluminum driveshaft in conjunction with a B Body differential, as I'm considering using that instead of an 8.8 from a Fox Body Mustang. That reading led me to a few people actually using the whole Crown Vic diff (up until '97) and upgrading the guts, and one of those people is tokarz1. Apparently the Vic's UCA ears are in almost identical positions as the G Body (Mustang isn't), the lowers are also very close, the spring perches are off by 1/2", and the rears are fairly cheap and plentiful since they're in multiple cars. They're a bit wide and need shortened, and it seems that using UCA for a 73-77 A Body would be beneficial.
8.8 rearend build
I know just like the 305 build not everyone is going to approve of what I'm doing and some will feel it's completely sacrilegious and that's ok, everyone likes what they like and are free to state their opinion and do what they like on their own car. I enjoy building things, the planning...
www.montecarloss.com
Members have suggested the Crown Vic rear... I'm happy I found this 8.5 core. I think I know where there might be another one. When I get through this maybe I'll be a bit more confident. This upgrade is forcing me to learn some useful things that make me feel like less of a waste of skin sitting at my desk all day long.I'm also just now catching up on this thread. Others such as Clone Tie Pilot, GNVAIR, and RT Jam have mentioned the Ford Crown Vic rear and coincidentally I've been reading up on it lately. Another member, tokarz1 did a real nice job setting his up.
I was looking at using a shortened P71 Crown Vic aluminum driveshaft in conjunction with a B Body differential, as I'm considering using that instead of an 8.8 from a Fox Body Mustang. That reading led me to a few people actually using the whole Crown Vic diff (up until '97) and upgrading the guts, and one of those people is tokarz1. Apparently the Vic's UCA ears are in almost identical positions as the G Body (Mustang isn't), the lowers are also very close, the spring perches are off by 1/2", and the rears are fairly cheap and plentiful since they're in multiple cars. They're a bit wide and need shortened, and it seems that using UCA for a 73-77 A Body would be beneficial.
8.8 rearend build
I know just like the 305 build not everyone is going to approve of what I'm doing and some will feel it's completely sacrilegious and that's ok, everyone likes what they like and are free to state their opinion and do what they like on their own car. I enjoy building things, the planning...
It took me a solid hour to get this rear pinion race installed. It kept trying to go sideways.
Here's a trick for you to learn..
Use the whole new Bearing to install that Race, as well as the other one. Put it on the Bearing, put them in the freezer for a couple hours, goes right in. 😉
Use the whole new Bearing to install that Race, as well as the other one. Put it on the Bearing, put them in the freezer for a couple hours, goes right in. 😉
Something like this works extremely well. It's small and can be rotated to watch the torque while spinning. Snap On makes one that uses a light that can be set to illuminate a desired setting - it's pretty slick, but $400.
Using a fish scale is 'old school' and effective, but takes a fair amount of space.
What I meant by it will seem tight is that 25-40 in/lbs of rotational torque will not spin freely by hand - in my opinion it feels tight, almost too tight. But it won't be.
I'd strongly recommend making a setup bearing for the inner pinion.
Dial Torque Wrench Needle Indicator Cursor Tool 0-100n.m 2-direction 33*10*8.5cm | eBay
Find many great new & used options and get the best deals for Dial Torque Wrench Needle Indicator Cursor Tool 0-100n.m 2-direction 33*10*8.5cm at the best online prices at eBay! Free shipping for many products!
www.ebay.com
Using a fish scale is 'old school' and effective, but takes a fair amount of space.
What I meant by it will seem tight is that 25-40 in/lbs of rotational torque will not spin freely by hand - in my opinion it feels tight, almost too tight. But it won't be.
I'd strongly recommend making a setup bearing for the inner pinion.
HIGHLY suggested. Agree with this completely. The rear pinion bearing closest to the gear is what he's talking about. If you don't use one during setup, and you miss on pinion depth, you'll might be buying a new one anyway after pressing the bearing back off if you mess it up or at the very least, waste a bunch of time doing it.
You can buy them already honed for slip fit from many rear-end specialist places for lotsa $$, usually around $75-100, but it's not tough to make your own. Ideally, you would want to stick with the same brand/part number NEW bearing if possible due to the likelihood of the closest match in tolerances, but if the used bearing is good, you could use it in a pinch. Cool thing is, mark it, put it back in the box when you're done, stash it in your tool box or whatever, and if you ever need one again, presto. There it is.
Here's an example of how to make one. He did it for a side bearing on a Dana, but same procedure. A few ways to skin this cat but basically...
