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Fugitive861 · 09-08-2019, 06:09 PM

I'm not sure why many of the photos are sideways or upside down. Some may be challenging to make out.

Our new-to-us F53 Bounder, V10 and 4R100 transmission had a small leak on the parking brake assembly which is located on the rear of the transmission. Before I ordered the $800 “remanufactured” unit I decided to remove ours and disassemble. If overwhelmed, we’d order the part. Fortunately we were able to put new bearings, seals, shoes and cap in it and all is good.

First removal is pretty straight forward, remove driveshaft, disconnect brake cable and unbolt from transmission. I did jack on rear tire up slightly to be able to rotate driveshaft to gain access to upper driveshaft bolts. A little fluid came out of driveshaft bolts which indicated leak was just the cap. I didn’t pick up on that until after I contaminated the shoes with ATF, so had to completely disassemble to get to shoes. Also, as on photo, ATF was on underside of motorhome indicating the cap was leaking, coming out of the driveshaft bolts…I also did not pick up on that.

Once the unit was out, I attempted to measure bearing endplay and got 0. Since I didn’t have a 2 9/16 socket I used an air chisel with sharp blade to loosen large nut, which worked really well. I also marked the drum and flange as they are balanced together and need to go back in the same orientation.

Each bearing is pressed onto the shaft. Once the large nut was off, I ran a wood screw into the forward seal and pried up with a pair of pliers to remove the seal. Next, placed unit on three blocks which caught the lip of the light gauge backing plate. Tapping on the shaft with a hammer and wood block worked to remove the shaft and forward bearing. Fortunately the light gauge backing plate did not deform. The rear bearing and rear seal stay on the shaft.

Fugitive861 · 09-08-2019, 06:11 PM

I had to use a press to get the drum off of the shaft. Then, used a sharp chisel, then broad chisel to start moving the rear bearing off the seat. Then long chisel to keep tapping it off. After removing the cap in the center of the shaft, I believe I found the leak as seen in photo. I would have been able to simply replace the cap if I would have figured it out before spilling ATF on the shoes. Besides I fixed the no-end play situation so I’m happy about that. Used die grinder and surfacing disk to clean up inside of drum.

Fugitive861 · 09-08-2019, 06:12 PM

By this time I’ve decided to do the rebuild myself ordered $200 worth of bearings, seals, cap, shims, shoes. I didn’t have a 2 9/16 socket so I welded up one. The races were easily replaced with a long punch, again alternating from side to side. The new rear bearing and seal go into the housing. The new cap with in with a coat of sealant.

Fugitive861 · 09-08-2019, 06:13 PM

I bolted the shaft/drum assembly to an angle iron held in a vice to be able to torque the nut to the required 220 foot pounds. The shims on the shaft determine bearing end play. Adding shims presses bearing slightly further apart thus riding looser in the races. Since I had 0 end play I added two of the thin shims…0.12 mm, I believe. I was lucky and that worked out perfect as I had 0.003 end play when the nut was torqued. I used the old nut to test end play and the new nut once proper end play was achieved. In the photo you can see the shoes exposed between the drum and backing plate. That is because the rear bearing is not seated. Tightening the large nut presses rear bearing down the shaft. But when the forward bearing bottoms out on the shims the bearing are super tight because the rear bearing is not fully against the seat. I set the unit on the blocks and gave a few pops on the shaft with a sledge and block of wood to fully seat the rear bearing.
One problem I realized, if the shims need to be adjusted, there is no way that I know of to just remove the forward bearing. The whole shaft would need to be removed which would pull the rear bearing seal out. The rear bearing would then need to be removed again, and probably a new seal installed. I suppose assembly with no rear seal would be prudent to determine shims needed then final assembly could be done with seal installed.

I installed back onto the motorhome, then filled with Mercon V with a large syringe. The transmission continued to leak slowly out of the rear, probably about two quarts. I drained and replaced filter at that time.

All in all I had, perhaps, 7 hours and $200 in this project. No one step was hard but I got lucky with the shims. I think most people would be better off buying a rebuild unit, but if your going to do it yourself I hope this helps.

wackymac · 09-09-2019, 05:18 AM

Have you test-run it yet?

RELHUB · 09-09-2019, 11:29 AM

Nice Job
Nothing better then being able to repair it your self

Waiter21 · 09-09-2019, 11:52 AM

Great writeup. I'll do mine next spring

chboone · 09-09-2019, 11:48 PM

Good write-up. Anyone interested in servicing the E-brake themselves might be interested in this older post.
http://www.irv2.com/forums/f23/emerg...f53-78154.html

Happy 01 · 11-04-2019, 04:35 AM

Has anyone experienced fluid coming out of the vent on the top of the unit? I installed a rebuilt unit and drove approx. 4 miles and checked it. Fluid coming out top vent. I added approx. 1.5 oz. It only holds 4.0 oz. Any ideas?

twinboat · 11-04-2019, 06:39 AM

Quote:

Originally Posted by Happy 01

Has anyone experienced fluid coming out of the vent on the top of the unit? I installed a rebuilt unit and drove approx. 4 miles and checked it. Fluid coming out top vent. I added approx. 1.5 oz. It only holds 4.0 oz. Any ideas?

If the bearing preload is to much, the bearings will get hot.

If the shoes are draging, it will get hot.

Heat can boil the fluid.

House Husband · 11-04-2019, 09:02 AM

Quote:

Originally Posted by Happy 01

Has anyone experienced fluid coming out of the vent on the top of the unit? I installed a rebuilt unit and drove approx. 4 miles and checked it. Fluid coming out top vent. I added approx. 1.5 oz. It only holds 4.0 oz. Any ideas?

I had the same issue with a new aftermarket ZF brake assemble from Allstategear. The bearings had been packed with grease when assembled and caused the ATF to pour out the vent.
I removed, disassembled and cleaned all the grease out of the brake assy. Problem solved.

Happy 01 · 11-06-2019, 04:37 AM

Thanks for the reply on this. I did notice that there was grease mixed in with the transmission fluid. Could you explain the theory as to why the grease would cause it to leak out the vent? I would think the grease would make the transmission fluid thicker and not leak as much and/or as fast. Is there a way to flush the grease out without taking the unit apart? Again, thanks for the reply, I would just like to know how you figured out to get the grease out, and why.

Fugitive861 · 11-06-2019, 08:46 AM

So, does Allstate Gear use grease in lieu of ATF for bearing lubrication? Do they tell the purchaser that? Are you supposed to NOT run in the unit? I'd be a bit upset if I bought an $800 unit and had to remove it, disassemble, clean and reinstall.

House Husband · 11-07-2019, 10:46 AM

Quote:

Originally Posted by Happy 01

Thanks for the reply on this. I did notice that there was grease mixed in with the transmission fluid. Could you explain the theory as to why the grease would cause it to leak out the vent? I would think the grease would make the transmission fluid thicker and not leak as much and/or as fast. Is there a way to flush the grease out without taking the unit apart? Again, thanks for the reply, I would just like to know how you figured out to get the grease out, and why.

I don't have a clue as to why the grease would cause the ATF to pour out the top vent. I can only state what I observed. The ATF coming out the vent was very viscous, indicating there was grease present. Yes Allstate's instructions did say to add 4 ozs. of ATF. As a quick patch while in the road, I used some plastic airline and fittings to extend the vent to in front of the radiator and terminated the air line in a Gatorade bottle.
When I contacted Allstate Gear, all they offered was to return the assembly for rebuilding, which left me grounded until the assembly was returned.
When I got home I took the ZF brake assembly apart, washed the grease out and reassembled with new seals.
I have nothing good to say about Allstate Gear and their products.