The Stovebolt Site Forums The Parking Lot Tons 'o Fun HO52 Pinion setup confusion

Putting an ho52 back together today. Got fresh carrier bearings, pinion seal and pinion bearing. Am trying to make sense of how the pinion bearing is secured in the housing. With the same amount of shims in the barrel as before teardown, i can get the backlash and gear pattern really close. Only problem is the pinion cap has about a sixteenth gap between the differential housing, which would create a challenge to seal it up. Changing shims directly changes the gap obviously. With no shims in, the gap is almost closed but that compromises backlash and pattern. Is that space supposed to be there for a gasket? Would make sense to me that the cap is flat to the housing and the shoulder on the cap that touches the bearing race has a slight amount of gap between the race. Likely did a horrible job of explaining that so I can include pictures or a diagram if necessary.

Thorens,

I think it might help get some replies to your questions if we know what truck you are working on?

Can you share a bit more info so folks might be able to offer some help?

If you only changed the pinion bearing you should start with the same thickness shim (s) that you removed. Install the retainer, with gasket if you have one, then install the yoke. Get your back-lash adjusted then check your gear mesh pattern. If it's not correct you'll need to remove the pinion assembly and either add or remove shims to set pinion depth, re-intall, set back-lash, check mesh pattern.....etc. Others have said that they have successfully used silicone in place of the paper gasket

Here's a link to a shop manual, check out the section 4-16, Rear Axle. Good guidance on major repair.

http://chevy.oldcarmanualproject.com/shop/1954truck/index.html


Here's a couple files that might help?

Yeah I've sifted through the manual but haven't found any mention of taking up that space that could occur if many shims are required. Unless you're just supposed to install as many gaskets as it takes to take the space up? I guess a proper way to phrase my question would be- is the pinion bearing race supposed to 'float' a few thousandths in the bore or is is supposed to be 'crushed' by the retainer cap? I'm using the exact shims that came out of it so I'm not sure quite what I'm missing. Thanks y'all.

You have it right. The pinion assem. is locked in by the flange up against the brg. There is a thick cork gasket that fits in the gap. You can adjust the pinion depth with the shims to get the best gear pattern without the gasket. Then lock it up with the gasket behind the flange. If you can't get a gasket for it you can use a heavy bead of RTV. Let it set up good before you fill it with lube.

George

There are two setup procedures, same as a 9" Ford axle that was used in NASCAR for many years. Use whatever pinion bearing shims are necessary to get the bearing preload correct- - - - -THEN set the pinion depth and tooth contact pattern by using shims between the pinion carrier and the housing- - - -NOT gaskets that can compress and upset the tooth contact. Using the same shim pack that came out is a mistake- - - -you'll need to compensate for whatever manufacturing tolerances the new pinion bearings might have by changing shims until you get the right preload.
Jerry

Thorens, is your replacement pinion brg. the double row ball brg. or the 2 roller brgs. with the spacer between them.
You have never said what year you have.

George

It's the style with two roller bearings with spacer between. The carrier is from late sixtys, early seventies but from what I can tell it's not much different than the other Eaton HO's I've torn town from the 40s.


Excellent thanks, hoping to get contact as close as possible to what it was before to avoid introducing some noise from the gears.

Sometimes that center "spacer" is actually a crush sleeve. It's too long initially, with a slight bulge in it, and the pinion nut is tightened a little at a time until the drag on the yoke is the correct torque in inch-pounds. Once that is done, then the backlash and tooth contact pattern gets adjusted. It's a "one and done" situation- - - -overtighten it, and you'll need a new sleeve to try again.
Jerry

No crush sleeve on the H052 or HO72 Eaton. The center spacer for the pinion bearing is matched to the two bearings so that when its assembled the yoke applies force against the center race and the retainer forces the outer race against the shims in the carrier housing creating preload. The shims are used to set the pinion depth which establishes the mesh pattern with the ring gear. Backlash is adjusted using the adjusters. I strongly caution against attempting to do a rebuild without the benefit of a shop manual. Below is a helpful link:

http://chevy.oldcarmanualproject.com/booklets/47stra/index.html

Have a shop manual, just wanted to clarify how the pinion bearing was secured in the bore and if a mild gap at the sealing faces was normal.

Sure way nicer to work on than a differential with a crush sleeve, just too bad parts are expensive and scarce for these Eatons.

Where did you get the pinion bearing? The double tapered roller was frighteningly expensive last time I went looking; so expensive that I just got a serviceable assembly from a bone yard.