Diff build

Lee Martin · #1 17-02-2010

Enjoy!!!

http://www.trfracing.co.uk/page_1265187551237.html

makinwaves · #2 17-02-2010

Nice guide Lee.

Can I ask why you remove the lugs from the pulley? I had a lumpy feeling diff when I built the 511 and wondered if it may have been the lugs, but chickened out of lopping them off.

Lee Martin · #3 17-02-2010

no need for them. Need the balls to work, not fail on the lugs

DCM · #4 17-02-2010

sometimes, it can stop you getting the correct tightness on your diff, they are there to stop the pulley from wobbling, but end up getting in the way.

makinwaves · #5 17-02-2010

Cheers guys, they will be lopped at the next rebuild.

chrispattinson · #6 17-02-2010

Excellent guide, thanks.
Just one question, I understand it is important to get the thrust bearing the correct way round. From looking back on previous threads, it appears the curved side faces the screw head. I seem to have trouble identifying the curved side, is this the side where the brass centre insert protrudes a little more?

simoncrabb · #7 17-02-2010

I'd never spotted those dimples before, but rarely had an issue with them, I suspect they wear in a bit!

I wonder why they are there, they aren't all the way around...

I'll chop em off in future tho.

DCM · #8 17-02-2010

Quote:

Originally Posted by chrispattinson

Excellent guide, thanks.
Just one question, I understand it is important to get the thrust bearing the correct way round. From looking back on previous threads, it appears the curved side faces the screw head. I seem to have trouble identifying the curved side, is this the side where the brass centre insert protrudes a little more?

the brass center sleeve, one side has a square shoulder, the other side is rounded, rounded side goes to the screw head, otherwise you can cut the head off.

chrispattinson · #9 17-02-2010

Quote:

Originally Posted by DCM

the brass center sleeve, one side has a square shoulder, the other side is rounded, rounded side goes to the screw head, otherwise you can cut the head off.

Thanks DCM

94eg! · #10 17-02-2010

You know it's a million times easier to sand the diff rings if you use the female outdrive as a ring holder. A small dab of grease will keep it stuck to the outdriveso it doesn't fall off if you pick it up. Only using your finger creates uneven sanding pressure across the face and is a PITA as well. Muchmore even sells a magnetic tool for prepping diff rings. Of course it costs money that could be better spent on other things...

I also use a little blob of bearing/machine oil on the sand paper to act as a lubricant when sanding the rings. This keeps bits of abrasive from getting imbedded into the metal. Just clean them with detergent or motor spray when your done. Buttery smooth diffs every time...

mikeyscott · #11 17-02-2010

The front diff tighter than the rear etc. is this the general rule of thumb on 4WD?

94eg! · #12 17-02-2010

Quote:

Originally Posted by mikeyscott

The front diff tighter than the rear etc. is this the general rule of thumb on 4WD?

Yes that's for both touring and off-road.

DaveG28 · #13 17-02-2010

Quote:

Originally Posted by mikeyscott

The front diff tighter than the rear etc. is this the general rule of thumb on 4WD?

It's something I've always tried to do, just to give a slightly safer split in power handling wise (tho I've always guessed at that being the effect!)

mikeyscott · #14 17-02-2010

Quote:

Originally Posted by 94eg!

Yes that's for both touring and off-road.

Need to rebuild the front diff anyway so cheers.

5POINTSTAR · #15 23-02-2010

I have read this thread and have learned nothing new

Lee Martin · #16 23-02-2010

Superstar!

T4miy4 Guy · #17 23-02-2010

Quote:

Originally Posted by 94eg!

You know it's a million times easier to sand the diff rings if you use the female outdrive as a ring holder. A small dab of grease will keep it stuck to the outdriveso it doesn't fall off if you pick it up. Only using your finger creates uneven sanding pressure across the face and is a PITA as well. Muchmore even sells a magnetic tool for prepping diff rings. Of course it costs money that could be better spent on other things...

I also use a little blob of bearing/machine oil on the sand paper to act as a lubricant when sanding the rings. This keeps bits of abrasive from getting imbedded into the metal. Just clean them with detergent or motor spray when your done. Buttery smooth diffs every time...

Great post thanks !

Andy

chrispattinson · #18 23-02-2010

Ive followed the guide to the letter, and must admit my diffs are smoother than ever before..... however.

After running in on the bench for the required few minutes, the diff did spin for about half a second when I spun the wheel (Ive never had a ball diff do this before without slipping).
Sure enough, the diff must have backed off a bit, or bedded in during this period, as it did slip, as Lee predicted in his guide.

However, when I nip it up by the tiniest amount, where it doesnt slip, it no longer spins as freely (which I expected).

Are you guys ending up with a diff that doesnt slip (when holding the spur and trying the rear wheels), and at the sametime get a very free diff action where the wheel will spin for 1 second?
It seems I can have a slipping diff that spins for 1 second, or a non slipping diff that doesnt really spin, but still has a smooth diff action.

Any thoughts?

simoncrabb · #19 23-02-2010

Which balls and thrust did you use Chris?

I've found a big different in steel balls & thrust v ceramic balls & thrust. The latter is a whole lot more free.

(And ceramic balls and a steel thrust sits somewhere in the middle.)

Lee Martin · #20 23-02-2010

if it doesnt really spin much this is not too bad. its only bad when diff slips. my diff at present is slipping for only 1/2 second. not much at all really. feel free to have a 'feel' of mine