34 replies to this topic

[andyt]

I have been putting my diff back in and checking the measurements that I have with the diff pushed hard against the clutch side , the clutch side housing and gasket done up with the lower two bolts. Now with the rad side housing done up by hand and no gasket I have a 16 thou gap between the bearing and housing, my gasket is 11 thou crushed would a 15 thou be the correct size shim?

This is an A+ gearbox with thrust bearings.

 

Andy.

Edited by andyt, 23 January 2016 - 08:02 PM.

[Spider]

Some of the bearings getting about only state a 0.001" preload, but that's usually stated on the bearing box.

 

If there's nothing on the box, then yes, what you've worked out is correct.

[andyt]

In the older Haynes manual it states that the bearings with Thrust written on them must have an 11 thou preload, this is what I based my calculations on. 

[Spider]

Apologies - I missed one of the measurements you wrote in your initial posting.

 

Now;-

 

In the older Haynes manual it states that the bearings with Thrust written on them must have an 11 thou preload, this is what I based my calculations on. 

 

   Cricky!   Mmmm,,, I think you'd have some burnt out bearings with that much pre-loading!  I've just looked in a Haynes manual I happen to have and this one does say 0.011" without the gasket - which these days, is a fairly onerous way to state it as the gaskets as supplied in are different thicknesses.

 

OK, the Factory info on the A+ Gearboxes / Diffs says a 0.004" Preload.

 

Can we just go back a few steps here just to be sure?

 

Place the diff in the gearbox and bias it all the way towards to the flywheel side, fit the diff cap, on with spring washers and bolts, do up the bolts BUT just until they touch the spring washers and then about 1 - 1/2 flats more, so that the cap is firm but definitely not tight.

 

Fit up the Flywheel side Cover with the gasket and all bolts, do the two that are in the case right up and then just nip the other 3.

 

This removes any free play from the bearings and applies a bias in a preload direction as well as squaring up the bearings.

 

Fit up the radiator Side Cover by hand as you have, no gasket, measure the gap.

 

Preload for the A+ is 0.004". The earlier boxes were 0.001 to 0.002" (and this is all I ever use).

 

So, let's say the gap is 0.016 and the gasket (crushed) is a measured 0.011", viz;-

 

0.016 - 0.011 = 0.005"

 

So at that, no shims would be needed.

 

However, from my experience, this doesn't seem right as they always need some shims.

 

Another example;-

 

Gap (no gasket) 0.008"

 

Gasket 0.011"

 

The 0.008 - 0.011 = - 0.003" (note this is a negative figure, which is what I'd expect)

 

-0.003 + 0.004 (preload) = 0.007" Shim.

 

Sorry for the long winded reply, but I wanted to be sure you have the right info as what you have initially found doesn't look right to me.

Edited by Moke Spider, 24 January 2016 - 08:50 AM.

[andyt]

Ah! the measurements that I took are defiantly correct, the smallest shims I have are 5 thou would this be ok to fit?   

[Spider]

If all your initial measurements are correct, then you need no shims, viz;-

 

measured gap (no gasket) 0.016"

 

gasket 0.011"

 

0.016 - 0.011 = 0.005" Preload

 

I can't say I've ever found a diff that needed no shims.

 

Respectfully, did you bias the diff all the way towards the flywheel before fitting up the cover on that side?

 

And when you fitted that cover, did it move the diff over the other way as you did up the bolts?

Edited by Moke Spider, 24 January 2016 - 08:52 AM.

[Lukie-J]

I have a couple of questions regarding this:

How do you know the crushed thickness of the gasket?

Where can I buy shims!?

Thanks,

Luke

[greenwheels]

According to my Haynes manual and a AKM6353 Rover manual the gasket thickness is .007 - unless anyone else is wiser.

[Ethel]

The crushed thickness is stated in workshop manuals, hence why we should buy OE quality gaskets. Failing that, you'd need 2 from the same batch - one to use, one to measure and a dial gauge, or feelers with a cutout in the test gasket.

Pretty sure my diff was shimless maybe it's an A+ thing?

[Spider]

I wouldn't use the figure in the workshop manual for the gasket thickness. I think just about all gaskets these days are non-OEM. Of the ones I've been buying, I've found them from 0.008 to 0.015" thick.

[dklawson]

+1 for Spider's comments.  Do not trust the gasket thickness quoted in the manual.  The manual was printed years ago and current gaskets, regardless of source, will not be the same as years ago. 

 

My advice, buy an extra gasket or two.  Measure one before installation, tighten to the specified torque, then remove and remeasure the thickness.  That will give you a realistic value to use in calculating the preload shims.  

[minimikej]

I've bought some new differential bearings for my rebuild. Bought from 'one stop gearbox shop' here http://www.ebay.co.uk/itm/191100753189

 

Now, there's nothing wrong with them, and I have no complaints.

 

These are branded, sealed, Japanese Nsk Rls11. I am looking for supporting evidence about the claim in the advert that there is no need to set preload with this type of bearing. The bearing certainly has no thrust markings on either side. Can anyone advise? Ta

[absx2]

Hi, they appear to be a deep groove bearing manufactured in Shandong China or Japan. So I guess the deep groove has no need for preload?

The country of origin varies throughout the brand and the pic on ebay does not appear to show a seal which would be a bad idea anyway.

The sealed bearings usually have Z or RS on the end of the number

Info at      www.terry-bearing.com      Ok its not the correct number but I found this

NSK deep groove ball bearing 6008:

 

1. Features:

Deep groove ball bearings mainly take radial load, also can bear radial load and axial load at the same time.When its only bear radial load, the contact Angle is zero.When deep groove ball bearings with larger radial clearance, with the performance of angular contact bearings, can withstand large axial load, deep groove ball bearing friction coefficient is small, the limit rotational speed is high.

 

2. Bearing Character:

Deep groove ball bearing is the most representative of the rolling bearing, widely used.Suitable for high speed and high speed running, and very durable, need not often maintenance.These bearing small friction coefficient, high limit speed, simple structure, low manufacture cost, easy to achieve high manufacture precision.Size range and variety in form, used in precision instrument, low noise motors, automobiles, motorcycles and general machinery and other industries, is the most widely used type of bearings in machinery industry.Mainly bear radial load, also can withstand a certain amount of axial load.

 

If yours are made in Japan like the SKF they should be a good bearing, I could do with some myself so i`ll wait for the experts to cast their opinion.

 

This is the bearing that minispares sell and MS states it needs a 1-2 thou preload. you will note it is also a deep groove bearing 

 

 

• Model: LJ1.3/8 (RLS11) RHP
• Shipping Weight: 0.333lbs
• 10 Units in Stock
• Manufactured by: RHP

 

"LJ1.3/8 (RLS11) - DEEP GROOVE BALL BEARING - 1.3/8 X 3 X 11/16"

INSIDE DIAMETER

34.925mm = 1-3/8 Inch

OUTSIDE DIAMETER

76.2mm = 3 Inch

WIDTH

17.46mm = 11/16 Inch

CLEARANCE

Standard

SHIELDS / SEALS

None

 

 

 

Edited by absx2, 08 June 2016 - 03:22 PM.

[Spider]

I've bought some new differential bearings for my rebuild. Bought from 'one stop gearbox shop' here http://www.ebay.co.uk/itm/191100753189

 

Now, there's nothing wrong with them, and I have no complaints.

 

These are branded, sealed, Japanese Nsk Rls11. I am looking for supporting evidence about the claim in the advert that there is no need to set preload with this type of bearing. The bearing certainly has no thrust markings on either side. Can anyone advise? Ta

 

Many I fit are this brand and type. As absx2 has said, they are a deep groove bearing, so can be fitted either way, though the normal convention is to have the writing facing out.

[minimikej]

Many I fit are this brand and type. As absx2 has said, they are a deep groove bearing, so can be fitted either way, though the normal convention is to have the writing facing out.

 

 

Ok, that;s what I've done. What would you set preload to?

Cheers