Ford 9" experts please come in

[Van B]

I had a local fabricator build a 9" housing for me when he installed my Ride Tech 4 link a couple of years ago. My question centers around the axle bearings. At the axle housing ends he used my existing Baer caliper mounting bracket as a bearing retainer. Between the retainer and the housing ends he put spacers measuring .200 or thereabouts. With it assembled this way, there was .040-.060 of movement when you pushed the axle in and out. This probably explains my brake knockback with floating calipers.

Without those spacers there is very little movement, but I am concerned about how much pressure can be put on the tapered roller bearing. There is a small gap between the bearing retainer and the housing end. Is this normal or acceptable? I have attached a picture with it assembled and with the bearing retainer/caliper bracket out of the way. The assembled photo was taken before the spacers were removed. The gap is slightly smaller without them.



Your input is appreciated.

[68protouring454]

generally, slide the axle all the way in and get the bearing so its seated, then measure bearing stick out, thats the amount of shim you want to use, maybe .005 less then bearing stickout. you dont want too much pre load bearing

[chicane]

0.008 to 0.020" is the number to shoot for. Tapered rollers can take more pre-load... think carrier bearings... they get more than that easily... but as stated, too much is too much.

[Van B]

Originally Posted by chicane

0.008 to 0.020" is the number to shoot for. Tapered rollers can take more pre-load... think carrier bearings... they get more than that easily... but as stated, too much is too much.

I test fit the passenger side without spacers and it was at bout .012. I am going to bolt it together tonight if it ever cools off outside. We're not used to 95 degrees here in WI.

[Apogee]

Is that a Moser #7900 or #7900FM housing end with a GM flange pattern and 80mm bearing bore? If so, the "FM" variant has a deeper counterbore for the bearing by ~.105" IIRC which could definitely be causing your issues if the .200" spacer originally provided was intended for the standard depth cbore. Based on the pictures, this is what I'm guessing happened, however I don't see the spacers in your picture...maybe I'm just being obtuse. A .105" shim instead of the .200" one should fix your problem given you have about .063" end play before and you want about .040" crush IMO on the oil seal which is preloading the bearing.

The SET20 oil seal (SKF#18881) needs a certain amount of crush to properly preload the bearing and minimize axial movement. If you look inside a seal prior to installation, you'll see that it has some little rubber ridges contacting the bearing that measure about 1/16" tall, and these compress fairly readily when you start torquing down the retainer bolts.

Tobin
KORE3

[Flash68]

That Tobin guy has some good knowledge.

[waynieZ]

Originally Posted by Flash68

That Tobin guy has some good knowledge.

And always willing to help!