Girling Diff End Float after diff rebuild

[Adrian Fuller]

Hi All

 

I am trying to set the end float on the half shafts following a full diff rebuild (crown wheel, pinion  bearings and seals) and having fitted new rear wheel bearings and seals, and having given the break backing plates a good clean up and coat of enamel paint (thicker than the original I am guessing). I did not measure the end float when I took this to bits but am now rebuilding and find that with the original shims fitted (approx 42" one side and 46" the other)I have no end float. I have backed off the bearing caps and I start to get an amount of end float with a bearing cap backed off on one side to about 50". Is this normal following this level of rebuild and should I get some more shims to get the correct end float or should I be thinking of stripping the diff again, which  obviously do not want to do.

 

Many thanks for any help with this

Adrian 

[BlueTR3A-5EKT]

Are the half shaft hub inner bearing cone assemblies pushed fully onto th half shaft and are abutting the shaft stop.?

Are the outer cups in the hub pushed fully home?

cheers

Peter W

[stuart]

Have you got paint on any of the flange faces?

Stuart.

[Adrian Fuller]

Hi

The bearings are all fully home and I have no paint where it would have an impact, however the hub is not fully torqued as diff is sat on a bare chassis so can not fully torque down, but I have gone as far as I can with an impact gun. 

[Ralph Whitaker]

Adrian, did you find the cause?  Re building the diff wouldn`t alter the length of the axle, so the loss of end float must be, as Peter W says, due to something not being right in the bearing assembly. Thicker paint on the backplates would increase end float. Hubs not being fully torqued onto the taper would be my guess as to why you have lost end float.

Ralph

[BlueTR3A-5EKT]

Not a daft question I hope.

did you refit the thrust button in the centre of the differential?  It transfers end float of axle shafts across the car.  In effect making the 2axle shafts one  long shaft.

item 76 here

[stuart]

53 minutes ago, BlueTR3A-5EKT said:

Not a daft question I hope.

did you refit the thrust button in the centre of the differential?  It transfers end float of axle shafts across the car.  In effect making the 2axle shafts one  long shaft.

item 76 here

I asked the same question when OP asked this on FB.No answer.

Stuart.

[Ralph Whitaker]

Surely leaving out the thrust button would create loads of end float, and Adrian`s problem is he has none even with 88 thou of shims.

Ralph.

[stuart]

41 minutes ago, Ralph Whitaker said:

Surely leaving out the thrust button would create loads of end float, and Adrian`s problem is he has none even with 88 thou of shims.

Ralph.

It works the other way round.

Stuart.

[iain]

+1. 

[Ralph Whitaker]

I bow to greater knowledge and experience, but after spending half an hour studying the sectioned drawing of the rear axle I still cannot understand how leaving out the thrust pad from the diff would reduce end float on the halfshafts. Unless I am missing something obvious, I cannot see what would stop the half shaft moving inwards until the brake drum hit the backplate. The whole idea being that the thrust is transmitted through the diff to the bearing on the other side.

Please someone enlighten me or I will not be able to sleep.

Ralph

[iain]

The two half shafts and the thrust button are effectively a continuous rod. Think of it as one shaft and the shims creating the end float, which should be equal on each side.

Iain

[Andy303]

9 hours ago, Ralph Whitaker said:

. Hubs not being fully torqued onto the taper would be my guess as to why you have lost end float.

Ralph

I am guessing that the thrust button is there.

The manual says to fully torque the axle nut before reassembly. If not fully torqued, drawing the taper of the axle shaft into the hub, I would think the axle/hub assembly is just long enough to take up the end float, possibly exacerbated by the both hubs/axles not being fully torqued. To my understanding the measured end float is the sum of the clearances between the ends of the axle shafts and the opposing faces of the thrust button, which is why both axle assemblies must be in place to properly measure the end float. When you make the measurement you are pushing one axle shaft against the thrust button which moves until it meets the end of the other axle shaft. With the hub pushed fully home, set the dial indicator to zero, pull the hub out and the indicated reading is the end float. If the shim packs are equal there would ideally be .002 to .003 clearance from either axle shaft to the thrust button, for a sum total of .004 to.006".

Edited December 19, 2020 by Andy303

[Ralph Whitaker]

2 hours ago, Andy303 said:

I am guessing that the thrust button is there.

The manual says to fully torque the axle nut before reassembly. If not fully torqued, drawing the taper of the axle shaft into the hub, I would think the axle/hub assembly is just long enough to take up the end float, possibly exacerbated by the both hubs/axles not being fully torqued. To my understanding the measured end float is the sum of the clearances between the ends of the axle shafts and the opposing faces of the thrust button, which is why both axle assemblies must be in place to properly measure the end float. When you make the measurement you are pushing one axle shaft against the thrust button which moves until it meets the end of the other axle shaft. With the hub pushed fully home, set the dial indicator to zero, pull the hub out and the indicated reading is the end float. If the shim packs are equal there would ideally be .002 to .003 clearance from either axle shaft to the thrust button, for a sum total of .004 to.006".

I fully agree.

 

2 hours ago, iain said:

The two half shafts and the thrust button are effectively a continuous rod. Think of it as one shaft and the shims creating the end float, which should be equal on each side.

Iain

Also agree. So if you leave out the thrust button ???. Loads of play in my mind. To have no play at all the thrust button must have been replaced.

[iain]

No, quite the opposite. You create the free play by inserting shims of equal thickness on both sides of the axle. The shims going between the brake backplate and the axle flange. If you have an axle set of shims, put them all back on, same thickness each side and then  measure the free play with a dial gauge. This will be measured easily if you tap one half shaft across the axle, thereby putting all the free play on the opposite side. Put you gauge on that side and measure how far the half shaft moves if you push it back to the opposite side of the car ( axle) that measurement is your current free play. Now if you need to adjust by adding or removing shims from both sides equally.

Hope  that helps

Iain

[Andy303]

1 hour ago, iain said:

No, quite the opposite. You create the free play by inserting shims of equal thickness on both sides of the axle. The shims going between the brake backplate and the axle flange. If you have an axle set of shims, put them all back on, same thickness each side and then  measure the free play with a dial gauge. This will be measured easily if you tap one half shaft across the axle, thereby putting all the free play on the opposite side. Put you gauge on that side and measure how far the half shaft moves if you push it back to the opposite side of the car ( axle) that measurement is your current free play. Now if you need to adjust by adding or removing shims from both sides equally.

Hope  that helps

Iain

I think we pretty much said the same thing, differently. The point of getting the shims evenly placed is so that the free play is nearly equal when measured at both sides to obtain the specified end float whilst centering the thrust block on the cross pin of the differential. 

Back to the original question, I do not see how a proper measurement can be made if the axle nut is not fully torqued.

[Ralph Whitaker]

Thanks chaps, I get all that, I re built my own axle last christmas. The point I was making was that it had been said adrian could have left out the thrust button. He already had 88 thou of original shims in place, and needed to slacken the hubs off another 50 thou to get any play at all. My reply was that the thrust button must be in place or he would not have had that problem, and I said that the fact his hub nuts were not fully torqued was probably the main reason for his problem. I torqued mine by holding the halfshaft in the lathe and jamming one of the studs (with a nut on) against the toolpost to prevent it turning. I can see it would be a problem otherwise.

Anyway hopefully he has it sorted as he has not come back on.

Ralph.

[Adrian Fuller]

Hi

Thanks for all the advice, I have added shims and have 5 thou end float but will plan on doing this alll again when I am able to torque the half shaft nuts up and see how much of a difference that makes. 

Thanks againn for all your advuce

 

Adrian