Replacing Pinion Seal B-61

[thomastractorsvc]

I went for a ride to my wife's work the day before yesterday and the rear pinion seal finally started puking instead of spitting up. So yesterday I changed the pinion seal on my truck so I thought I would post how to do it for posterity with pictures.

The tools required- Hammer, small chisel and punch, 9/16” socket, ¾” Socket, 2 ¼” socket, diagonal side cutting pliers (dykes), small ratchet strap or rope, cleaning solution and safety glasses.

Seal SKF 27452

Sleeve kit SKF 99275

1. Locate the rear axle yoke and u joint. Clean first as needed

2. Bend locking tabs back with small chisel or punch to release bolt heads that hold the u-joint caps to the rear yolk. Secure driveline with ratchet strap or rope. Carefully remove caps making sure not to lose the needle bearings from the cups. Maneuver u-joint and collapse drive shaft, move out of the way and secure

3. Remove cotter pin and nut, remove yolk

4. Remove seal housing bolts and remove, drive seal out, clean housing and replace pinion seal (coat seal with oil to prevent burn up on initial drive)

On mine I had to install a speedy sleeve as the seal had worn the pinion and would not seal

5. Clean carrier face and remove old gaskets. I made a gasket for mine, if you choose to do this make sure to use gasket shellac on both sides and don’t over tighten. Reinstall and tighten bolts.

6. Reinstall yolk (I oiled outer sleeve and splines to help assist with installation) make sure to "clock" the yolk in the same position as removed to maintain driveline alignment, install nut to 400-500ft lbs ( per page 154 Mack manual dated 1960), install cotter pin.

7. Reinstall drive shaft being careful to not damage u-joint, reinstall caps and bolts, bend locking tabs up to lock bolts. <<Be careful not to over tighten>>

8. Clean up tools, check rear axle fluid level and wash rear axle and frame area if required. Since you are already dirty this would be a good time to flush and refill the rear differential. Drain plug is locate on the bottom of the housing uses a 1/2" drive ratchet or breaker bar, plug on rear axel is a 5/8" housing holds about 3.3 gallons so you will need to buy at least 4 gallons of gear oil. I use 85W -140 GL 5 extreme pressure, others use 80W-90 or 85W-90. My opinion- I would rather have the heavier oil as it keeps noise down, same viscosity when cold as the other but not thinned so much in the warm weather. As a side note read the container and make sure what ever you purchase it meets Mack specs.

[Mike]

Looks like you have done enough work for one day, so now you can take it easy. Also you've done a good job and with photos and made it look easy. Now it is time to take a shower or bath. LOL

mike

[Freightrain]

Not a horrible job to do if you have a big enough bar to get the nut loose. Then it's all downhill.

[thomastractorsvc]

Larry,

Once I pulled the cotter pin I took the nut off by hand, I think that was part reason it was leaking, I had my 3/4 and 1" impact on stand by but used my high power 1/2" to tighten it is rated at 700 ft lbs, I got the nut close to where it need to go and waited for the compressor to turn off than hit again till the hole lined up.

Mike,

Its been so hot here I want to take a shower three times a day, I have the fan on in the shop and did most after dinner.

[mackniac]

this will be helpful for me as I will certainly have to do mine on my RB688 soon .

love the pics and explainations .

[Freightrain]

Ha...seems mine was the same way when I did it many years ago. Seemed odd, but I think the bearings wear and the bearing preload that was there 50 yrs ago is now gone? I assume it uses a solid spacer, not a compression version like say a Ford 9" would use? Or am I wrong(again)?

When I had the trans tailhousing off converting to electronic speedo, I removed one of the shims from the rear bearing to help with the looseness in the transmission. It did help a bit, as I only took out like a .005 shim(if I recall correctly).

I used to borrow a 1" impact from a friend, but finally found a nice IR version for decent money(lower end model). I put a 50ft 1/2" air line on my compressor and used a big fitting just for it. It does a nice job, better then nothing at all LOL!

[j hancock]

Just like being there to help except we didn't get dirty!

[thomastractorsvc]

J Thanks, next time don't be surprised if I holler out from under the truck and ask for something

[thomastractorsvc]

Ha...seems mine was the same way when I did it many years ago. Seemed odd, but I think the bearings wear and the bearing preload that was there 50 yrs ago is now gone? I assume it uses a solid spacer, not a compression version like say a Ford 9" would use? Or am I wrong(again)?

When I had the trans tailhousing off converting to electronic speedo, I removed one of the shims from the rear bearing to help with the looseness in the transmission. It did help a bit, as I only took out like a .005 shim(if I recall correctly).

I used to borrow a 1" impact from a friend, but finally found a nice IR version for decent money(lower end model). I put a 50ft 1/2" air line on my compressor and used a big fitting just for it. It does a nice job, better then nothing at all LOL!

My 1" is the HF 2000 ft lb spent 128 after sale and 20% coupon, I also have the 1/2" hose hook up but I thought it was funny that the fitting into that gun was only 3/8"

[Maddog13407]

wow,almost felt like I was under there getting greasy with you haha. ive seen those nuts bolts hand tight and so tight you had to heat them a little to get them loose. have seen where the last guy used #2 permatex on the splines or high tack to keep the grease from seeping out also. that makes for an interesting time getting the yolk off.

[Mike]

Just like being there to help except we didn't get dirty!

J, I was worn out after seeing the photos and was dirty and sweaty.

mike

[thomastractorsvc]

well it seems now the oil filter is leaking so off to find an o ring, keep the grease rags handy!

[Maddog13407]

ive taken those apart before where the Mack garage actually put two seals in back to back before to stop it from leaking. my grandfathers B42T is like that.

[thomastractorsvc]

I was going to pick up two new ones when I go drop the kids off for summer school, they are like $4 if a new one wont fix it then two it shall be. When I changed the oil a while back the o-ring had permatex on it but it was leaking then to.

[Maddog13407]

the pinion seals I was talking about I mean. any Napa should have the lubrifiner o ring and a little dab of permatex helps those to

[Mike]

I'm just wondering if the luberfiner seal has a part number on the bottom of it to match with Napa?I'd get me a new one.

mike

[thomastractorsvc]

Mike

Just put the new one on this morning seems to have stopped it from seeping/leaking. Makes a difference when they have flexibility. The O-Ring is the same for both the 500 and the 750 housings

The part number is -

Luberfiner 2788

Fleet Guard(Cummings) 101853S

NAPA FIL 5414

[Mike]

Mike

Just put the new on this morning seems to have stopped it from seeping/leaking. Makes a difference when thy have flexibility. The O-Ring is the same for both the 500 and the 750 housings

The part number is -

Luberfiner 2788

Fleet Guard(Cummings) 101853S

NAPA FIL 5414

Thomas,

Thanks for posting the numbers.

mike