Banjo carrier preload problem

[TBone69]

Ok so I am rebuilding my first banjo rear and have found Tom Endys articles invaluable.

I am the reassembly stage, I have cleaned everything, installed New bearings and races. Today I started going thru the preload process.

I noticed as I was bolting everything together without gaskets to make sure the carrier locked up there was a good gap between the left axle tube and center even before everything was tight once I started to tighten the bolts the carrier locked up.

The carrier came from a different rear as the carrier from this rear had a spun bearing.

So far I have added .055 worth of gaskets and the carrier just started to move with a lot of force. This doesn't seem right.

I double checked and made sure the bearings and races where seated all the way.

Before I remove the races and bearings and mic them and compare to the originals am I missing something? Has anyone had problems with bearings or races being out of spec?

I'll try and post some pics later.

[TBone69]

Finally figured out how to get pic for my droid phone to my iPad.

[Mitch//pa]

this doesnt help your issue but for the record you could have reused your old carrier with the spun bearing. a very easy fix ..i knurl all the carriers now needing it or not... makes for a tighter bearing fit

[TBone69]

I didn't have a knurling tool for the lathe but I had a spare carrier so I went that route. I still have the original carrier just in case I need it.

[andyfresno]

.055 is a lot - -I've done 5-10 of these and never seen over .045. more typical is .030.

There is no reason to use any part with a problem or repair, i.e, I wouldn't use your old carrier.

Sorry I can't help otherwise

[Vin-tin]

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TBone, are there any shims under the carrier bearings?
If there is, sounds like you might be able to remove one or two. If there's no shims, then I have no clue.

[andyfresno]

https://en.wikipedia.org/wiki/Knurling

"As auto parts have become less expensive, knurling has become less prevalent than it once was, and is specifically discouraged by performance engine builders.[2]
Knurling can also be used when a component will be assembled into a low precision component, for example a metal pin into a plastic molding. The outer surface of the metal pin is knurled so that the raised detail 'bites' into the plastic irrespective of whether the size of the hole in the plastic closely matches the diameter of the pin."

[CWPASADENA]

I like to see a bit less however, I have assembled many banjo rear ends. Years ago, I had one that was a bunch of mis-matched parts that was close to .060. I made a couple of thick gaskets using good quality sheet gasket material to take up most of the clearance. That rear end is still working well after 15 years.

That is what I did.

Chris W.

[andyfresno]

I defer to Chris as he's actually tried it and it works

[Tom Endy]

Originally Posted by TBone69

Ok so I am rebuilding my first banjo rear and have found Tom Endys articles invaluable.

I am the reassembly stage, I have cleaned everything, installed New bearings and races. Today I started going thru the preload process.

I noticed as I was bolting everything together without gaskets to make sure the carrier locked up there was a good gap between the left axle tube and center even before everything was tight once I started to tighten the bolts the carrier locked up.

The carrier came from a different rear as the carrier from this rear had a spun bearing.

So far I have added .055 worth of gaskets and the carrier just started to move with a lot of force. This doesn't seem right.

I double checked and made sure the bearings and races where seated all the way.

Before I remove the races and bearings and mic them and compare to the originals am I missing something? Has anyone had problems with bearings or races being out of spec?

I'll try and post some pics later.

If you have a good carrier that the bearings press onto I would use it. Add another .010 gasket and see where the pre-load is. I have put a bunch together with a lot of gaskets and they worked fine.

If you want to reduce the number of gasket and you have a lathe, take a cut on the bearing stops on each side of the carrier. This will reduce the number of gaskets. If you take too much off you can add shims under the carrier bearings. Bratton's has the shims, they are .005 thick. You can stack as many as you need.

Tom Endy

[harleytoprock]

Tom, After adjusting carrier bearings preload, what's an ideal amount of gasket thickness to end up with, that gives enough flexibility for gear backlash adjustmet?

[TBone69]

Great thanks guys! Being this was my first rebuild I was concerned with the amount of gaskets.

I'll have to order up some more gaskets and might as well get some threaded studs for alignment to make stacking gaskets a little easier. I had used a drift pin to get things lined up as I was bolting it together.

I'll post with results this weekend.

Thanks again
Tom

[Marshall V. Daut]

You mentioned that you're sure the new bearing races are seated. That could be true, meaning you drove them in as far as they would allow. BUT - it only takes a grain of grit on the bottom of the race or on the axle housing surface where the new race goes to keep the race from seating perfectly - and you'd never know the difference by eye-balling it. But the extra minute space created by that grit would move the race away from the housing enough to require the extra gaskets you seem to need. If you had kept the old races in place, the tolerances might have been within spec's. But the fact that you did install new races and are having trouble with an excessive number of gaskets to obtain proper assembly and pre-load adjustment tells me there just might be some crud behind one or both bearing races.
I would take the time now and remove both races and clean the mating areas until squeaky clean. It doesn't cost anything at this point to do so, just a little additional time. You probably won't even see what's there, but the cleaning process should remove whatever it is. Then re-install the races and check the number of gaskets required. Even if crud between the race and axle housing is not the problem, you can scratch that off your list of possibilities, knowing the races are properly and cleanly seated.
Marshall

[TBone69]

Thanks Marshall, I definitely plan on doing this though I thought I cleaned them very well the first time, maybe I missed something.

Easy enough to check and re clean. Heck who knows maybe there is even a shim behind the race that has "glued" itself in that I didn't notice while removing the old races.

[Marshall V. Daut]

Also ensure that when you removed the old races , no divots in the metal or other burrs were created that could keep the new races from seating perfectly. Chisels, screwdrivers and prying tools could cause these conditions. Run your finger all around the mating surfaces. If there is a burr, your sensitive finger skin will tell you so! Take some rough grit sandpaper and sand the housing 's race recess to ensure it's clear of burrs.
Marshall

[TBone69]

After much double checking of everything, seeing nothing wrong and not wanting to use many many gaskets I threw caution to the wind and started cutting.

I took .010 off of each side of the carrier on the first pass, put everything back together and carrier still would not turn. Tore everything back down and took another .010 of each side. I went through a few combinations of gaskets and ended up with a total of .045. The carrier turned so I installed my preload tool and Viola!!!! 20 inch lbs to get moving!!!!

So a little quick math would tell me I would have had to use .085 worth of gaskets. I boogered up the gaskets I had from so much trial and error so I will order another kit. Hopefully I can get away with 3 .015 gaskets but with my luck I will have to split it up to at least one .010 and .005 to get he backlash set. I will also make some studs for gasket alignment to help lining up gaskets.

I'm off to The Race Of Gentlemen next weekend so probably wont get back to work on the rebuild till the week after. Hopefully we will have a nice weekend of Indian Summer so I can get the rear painted once back together and get it hung in the chassis.

[Kevin in NJ]

One thing to do before assembly is to use a quality fine flat file and run it on the flat mating surfaces. You are not looking to take off any materials, but you are looking for high spots. If you find any you hold the file very flat and only take off the high spots.

You would be surprised at the minor spots the pop up. Not anything major, but it can only lead to a better result if you have the surfaces as flat as they can be.

[redmodelt]

I think Kevin is talking about the lip on the axle housings where they mate to the center section.

[Kevin in NJ]

I am talking about all the flat surfaces that mate together.

Off the top of my head.
The carrier halves, the banjo, the axle housings, and both surfaces of the torque tube.

The bearing press on surfaces hopefully are fine. I really like to see machine marks. Shiny is bad. I also like to see the lines across the faces of the gears (the broach marks).

[Tom Endy]

Originally Posted by TBone69

After much double checking of everything, seeing nothing wrong and not wanting to use many many gaskets I threw caution to the wind and started cutting.

I took .010 off of each side of the carrier on the first pass, put everything back together and carrier still would not turn. Tore everything back down and took another .010 of each side. I went through a few combinations of gaskets and ended up with a total of .045. The carrier turned so I installed my preload tool and Viola!!!! 20 inch lbs to get moving!!!!

So a little quick math would tell me I would have had to use .085 worth of gaskets. I boogered up the gaskets I had from so much trial and error so I will order another kit. Hopefully I can get away with 3 .015 gaskets but with my luck I will have to split it up to at least one .010 and .005 to get he backlash set. I will also make some studs for gasket alignment to help lining up gaskets.

I'm off to The Race Of Gentlemen next weekend so probably wont get back to work on the rebuild till the week after. Hopefully we will have a nice weekend of Indian Summer so I can get the rear painted once back together and get it hung in the chassis.

My experience has been that paper gaskets do not equate with metal shims. The paper will crush down, the metal won't. taking a total of .040 off the carrier hubs does not seem right to me. It seems excessive. I have never had to take a cut on a carrier. I only suggested it as a means to reduce the number of gaskets you were concerned about.

I also wonder about the torque wrench you are using. I use a dial indicator torque wrench and the reading I am looking for is after I overcome the inertia and have the bearings turning.

Tom Endy

[TBone69]

Thanks guys, I did run a flat file across the center and both axle halve flanges and did turn up a hi spot or two from some previous to me chisel work.

It did take quite a bit of force removing and pressing the bearings so I think I am good there.

[TBone69]

HI Tom,

The torque wrench goes to 20 inch lbs then once the carrier is turning drops down to 14-16 inch lbs, does this sounds right?

Thanks for all your feedback
Tom

Originally Posted by Tom Endy

My experience has been that paper gaskets do not equate with metal shims. The paper will crush down, the metal won't. taking a total of .040 off the carrier hubs does not seem right to me. It seems excessive. I have never had to take a cut on a carrier. I only suggested it as a means to reduce the number of gaskets you were concerned about.

I also wonder about the torque wrench you are using. I use a dial indicator torque wrench and the reading I am looking for is after I overcome the inertia and have the bearings turning.

Tom Endy

[tbirdtbird]

Originally Posted by Tom Endy
My experience has been that paper gaskets do not equate with metal shims. The paper will crush down, the metal won't. taking a total of .040 off the carrier hubs does not seem right to me. It seems excessive. I have never had to take a cut on a carrier. I only suggested it as a means to reduce the number of gaskets you were concerned about.

I also wonder about the torque wrench you are using. I use a dial indicator torque wrench and the reading I am looking for is after I overcome the inertia and have the bearings turning.

Tom Endy

[harleytoprock]

Nothing wrong with the torque wrench you are using for preload testing. 20 inch pounds is your reading to overcome the stiction to get it moving. Your 14-16 inch pounds is your actual preload drag.

[Mitch//pa]

a model A diff can be done by feel if you have experience in these things

[Dave in MN]

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Originally Posted by Mitch//pa

a model A diff can be done by feel if you have experience in these things

I agree Mitch. Trouble is, most of us don't know what the correct feel is. I just redid the differential on my Phaeton early this summer. I purchased a used inch-pound wrench to verify what I thought might be okay. I was in the range and the wrench gave me the good feeling of knowing for sure.
Now 80# to 85# for the mains...I can hit that every time with my breaker bar because of the number of engines I do. Experience...goes a long way!
Good Day!