The Stovebolt Site Forums The Parking Lot Big Bolts pinion nut

Hi all just want some suggestions on getting the pinion nut of my diff to replace seal. The truck is a 1942 1.5 ton chev with a single speed diff.

You are going to need a big socket on a3/4 drive air impact wrench.

I use a 4 foot pipe wrench braced against the floor to hold the pinion flange and a 3/4" drive socket and breaker bar with a 3 foot cheater pipe over the breaker bar. Be careful not to smash your knuckles when the nut turns loose!
Jerry

Wait, so are you saying I need to buy one of these?
http://www.harborfreight.com/48-inch-steel-pipe-wrench-1133.html
You may have just given me the excuse I've been waiting for for years now.

I think better than a pipe wrench is this little tool.
Most useful for holding the rear axle pinion.
Ratech Part number 18001 http://www.ratechmfg.com/Yoke%20tools.htm
Yoke holding tool PICTURE

Also like sort of like Lincoln said, you can use a piece of angle iron bolted to the flange, braced on the ground.

Right, I've made similar things with pipe and plate drilled to suit, still better than a pipe wrench I think.
But for $18 the tool from Ratech is ready to go, fits lots of different yokes, and fits in a tool box.

Didn't even see the price, I might have to get one for only $18

Use whatever is handy, but when the pinion nut on an Eaton or Spicer twin screw setup with 600 FT/LBS of torque on the nut is involved, the bigger the tool, the better! Don't send a boy to do a man's job!
Jerry

All these years removing pinion nut/flange and NOW I learn about this tool?! I just ordered one and look forward to using it. Thanks for this discussion.

I usually put a socket and breaker bar on with a pipe cheater,then just push the truck backward (or forward)

That, my friend, is an example of how not to do it. That has the danger of damaging a lot of things. Holding the yoke is the way to do it. Pipe wrench, store bought tool or fab a piece of metal to a C shape. I don't even like something that bolts to the strap holes. HRL, how the heck to you get to 600FT lbs and know it?

You spiked my interest, damage what things?
Been doing it that way for 40 years, never damaged anything.

40 years of good luck.(that could be one time for all I know) Side gears, spider gears, ring gear, pinion gear... teeth and their shafts. Bearings, seals, axle splines. Depending on age and condition of components. That way is not recommended by anybody. If the nut is corroded or rusted on, and you don't know it, you could cause internal damage for sure.

A longer arm on the torque wrench will give you relatively higher torque - below, supposedly, is the equation:

Here is the formula: M1 = M2 x L1 / L2

Where:

M1 is the torque setting of the wrench.

M2 is the actual torque applied to the nut

L1 is the normal length of the wrench

L2 is the extended length of the wrench (Length of wrench + length of adapter)

Example:
M1=torque wrench setting ?
M2=80 FT-LBS (Desired torque)
L1=18" (Length of torque wrench)
L2=22" (Total length of wrench with 4 inch extension added to wrench)
80x18/22=65.45 M1 therefore = 65.45; In other words if you want to torque a fastener to 80 FT-LBS using an 18 inch torque wrench with a 4 inch torque extender you will set the wrench to 65.45 FT-LBS

Richard D. Scherrer
airframe and powerplant mechanic - Kalispell, Montana

I M/whelmed

Bartamos
Sr. Wiseguy Fellow
ASU, Tempe, AZ

I use a torque doubler. My 3/4" drive deflecting-beam torque wrench measures 30" from the handle pivot to the center of the 3/4" square drive. I acquired a piece of 2" X 1/2" steel flat bar and cut a short 3/4 drive extension into 2 pieces. I welded the female end into a drilled hole in one end, and the male end into the other hole with 30" between them. 300 ft/lbs. indicated on the wrench equals 600 ft/lbs. at the nut. Of course, the wrench is 5 feet long! That's why a 4 foot pipe wrench is needed to hold the yoke. If more torque is needed, I'll just build a longer multiplier.
Jerry

I know TC knows and everyone knows, but in case.. this is not to be interpreted as adding a "cheater bar" (pipe)onto a torque wrench. This is a No-No. Adaptors/multipliers are the subject and the example equation is for a strap wrench. You can use all the socket extensions you want but no handle extensions in the form of a cheater bar!
The "longer arm" has to be on the square drive end as in Jerry's DIY Multiplier/TC's Adapter. Twice as long = half the torque.

"It would be nice to be able to draw a distinction between adapter and adaptor, but they are used interchangeably in all varieties of English and in all their meanings"

That's a nice tool, there. If I hadn't already fabbed one up from a piece of steel, I'd be buying one. Good find.

Using a pipe wrench on a pinion yoke is a bad idea. The teeth will dig into the yoke and may weaken it (sharp stress risers). Pipe wrenches also have a tendency to slip. They're made for pipes.

If your pipe wrench slips on a pipe or yoke, it's not set right. The "wedge" aspect must be set correctly, then it can't slip. Many have had good luck using Monkey's on yokes. True enough, using the right tool is best. The plumbers on here will leak all over this.

I bought a big, well-used pipe wrench at a pawn shop and dulled the teeth with an angle grinder. It holds just fine on the almost-square shape of a driveshaft yoke, but it sucks at grabbing onto a pipe or other round stuff now. I've got a huge chain wrench for round stock.
Jerry

I don't see any problem with rolling the truck forward or back to loosen the nut. Actually think it's a pretty good idea.
Unlikely that the torque on that nut would ever be more than engine torque X transmission first gear ratio, which better not harm the rear axle...

Of course, it's a free country. You can risk a failure or not.
When a motor drives a differential, a small pinion drives a big ring. "Mechanical advantage". It overcomes friction, stiction and force vectors. When you backup on a yoke, you have reverse mechanical advantage, whereas a big gear is acting on a small gear connected to a stationary nut needing xxx Ft lbs to break loose if not damaged or rusted. This could break something. You are also possibly jerking the drive train/nut/threaded connection.

(My high school auto shop teacher told us never to jerk a wrench when tightening or loosening. You will snap something because you can't judge/feel the torque you are applying).

Anyway that's my idea.
Dune's is a neat idea if you are in the boonies and have one wrench.
Otherwise it's not worth it in my opinion. The result would be VERY costly.

When there isn't room enough under the truck to use that 4-foot peice of pipe, I have always used a big pipe wrench on the yoke, braced against the floor and my 3/4 drive breaker bar with a socket on the nut and 12-ton bottle jack under the bar. Use a block of wood so the breaker handle doesn't slip off the jack. Then jack away. Works every time.

On a big truck tractor where you can get a good swing at the nut with a hammer you can swell the nut to break the rust with a big hammer and a big chisel or an air chisel it you have one. The air chisel works wherever you can't get a good swing. Make sure you can get another nut first.

Learn from my mistake. I had my front axle on jacks and front wheels off all winter to work on the engine. Then a few months later I decided to get into the pinion seal. I forgot the front end was on jacks and gave the pinion nut a good tug causing the wheels to turn and truck to move forward. The front jack stands rocked forward and then came back to rest. mjl

I still stand by my way of doing it with a breaker on the floor and rolling the truck!
Yes, I ran a truck shop for 15 years and that was the best and safest way to do it.

As for your delicate gears picture this.
Your driving a semi,80,000lbs gross, your pulling a steep pass, quite a bit of strain coming from that 600HP motor, you get to the top (and check your brakes of course ;]) down you go, you hit the jake switch and maybe the retarder if its a cat and you are now holding that 40 ton's and putting that same pressure ,Where? on the opposite side of those delicate gears.

or

Your driving a big bolt with a vacuum 2 speed, you push the lever to shift down and miss the gear (don't ask) you hit the throttle rev,grind,rev, grind and !BANG! it goes in, 90 times out of a hundred no damage is done to your delicate,weak little gears.
Did I mention this was the safest way to do it??

Too bad we don't have a "beating a dead horse" emoticon!
Jerry

Yes, that'll do just fine.

We've covered the original question quite well with various methods and opinions.

Before or in case this were to get out of hand let's call an end to it now.

Thanks for all the discussion,

Grigg