Rear swap issues

albertaborn

Daily Driver
Dec 29, 2015
37
0
0
I picked up in 8.5 out of a 1984 olds Hurst to swap in got the old 7.5 out and started building up the 8.5 as it was all tore apart in pieces. The first problem was it was missing a pinion yoke so I got one from a gear place but for some reason the seal surface is much too large for the seal that came with the overhaul kit that's the first issue so just wondering if there's two different pinion yoke SEALS or pinion yokes? The next issue comes with the wheel bearings I ordered the wheel bearings from the same gear place but the axles that buddy gave me to go with the tore a part 8.5 the bearing section measures 1.4 inches and is much too small for the bearings that came from the gear place I'm starting to wonder if I got the wrong axles or did I get the wrong bearings?
 

lilbowtie

Pro Stocker
Oct 5, 2004
1,736
0
0
Canton Mi.
Are you sure you have an 8.5 - the parts you got were for an 8.5(specific to 84-87) - I believe the wheel bearings for 7.5 and 8.5 are the same and you should have 28 splined axles.
 

albertaborn

Daily Driver
Thread starter
Dec 29, 2015
37
0
0
It's definitely an 8.5 from an 84 old hurst as far as the housing goes. It does have 28 spline axles as well. It was missing gears, pinion yoke, carrier and all bearing. Basically was a housing with main caps but he had what he thought are the axles as well so I took em. I found an article that talked about two different sizes for wheel bearing so I'm guessing I have the wrong wheel bearing size for my axles.
 

malicad

Dragway Regular
Dec 8, 2009
1,383
0
0
South Milwaukee, WI
General Motors is all about parts interchangeability. I doubt you have the right axles. GM wouldn't make 2 different size bearings (or seals for that matter) for a rear end that was only in a handful of cars. Just make sure the axles are correct. I would assume the 2 different sized bearings were probably for the 7.5" or 8.5" rear. Since the diameter of the axles are different, they might use different bearings. Or maybe I'm completely wrong, and they use the same bearing, but I wouldn't think so. The Grand National rear should be identical to yours, too.
 

albertaborn

Daily Driver
Thread starter
Dec 29, 2015
37
0
0
I guess for starters I would like to find out what all the dimensions are for standard 8.5 axles The way this whole transaction happened I wouldn't be surprised I have the wrong axle but would need some numbers to confirm.
 

albertaborn

Daily Driver
Thread starter
Dec 29, 2015
37
0
0
Well to add a little mystery to it all buddy isn't sure if it was outta of a grand national now. But it for sure is a 8.5 housing with the square protrusion on bottom and does have extra ribbing on the pinion area compared to my 7.5. Also does not have the diagonal cover. Other than center section it's all the same as my 7.5. I just bought wheel bearing and seals for a 7.5 and they do fit. So it seems like it's a center section from a 8.5 but with tubes from a 7.5 or something

Also not that this is very scientific but the axles do seem to belong by going how everything is painted
 

malicad

Dragway Regular
Dec 8, 2009
1,383
0
0
South Milwaukee, WI
Looks like I could be wrong. I looked real quick one Rockauto for replacement bearings, and sure enough, the same part numbers are listed for all years of turbo Regals, Malibus and your Cutlass. Says the 2.250 O.D./ 1.400 I.D bearing will fit both the 26 spline 7.5" rear, OR the 8.5" 28 spline rear. BUT, then there's also another larger bearing that's 2.530 O.D/ 1.620 I.D that says it's for the 8.5" 28 spline rear. So, wtf?!? That's why I have a guy who builds all my rear axles. I don't have to deal with this, lol.
 

albertaborn

Daily Driver
Thread starter
Dec 29, 2015
37
0
0
Yeah its been a dousie. But I do got it figured now. It definitely took 7.5 wheel bearing setup. The pinion also I had to remove the outer sleeve that was on there for it to fit my seal that came with the overhaul kit. So far I'm day number 2 of setting it up. It's kinda too bad the axles are smaller but at least I have the better ring and pinion advantages of going from a 7.5 to 8.5.
 

albertaborn

Daily Driver
Thread starter
Dec 29, 2015
37
0
0
Can anyone she'd some light on which side I should really be concerned about for a pattern? Drive or coast. Seem like my drive ain't bad but my coast is way on the toe
 

StreetBu

MalibuRacing Junkie
Mar 21, 2004
4,158
3
38
Upstate NY
The pattern has to be good on both Sides! I'm no good at setting them up, don't ask me which setting to change LOL
 

MalibuRacing.com Gear

Stickers & Shirts!!