Radius arms. which side is up - IRS First Time Rebuild

(Frank Andersen) #162

First, Mark; there was some discussion on the play spec some time ago. I ‘think’ the opinion was that the actual spec is 0.001 - 003". Some verification is called for?

Apart from that, your logic and calculations seems OK; the master spacers 0.15" is deliberately too thick, giving excessive play - so the thinner the shim the lesser your play.

Whether grinding shims is the right way to go about it; if you have an available supplier - getting the right one seems a better idea?

However; the shim is there only to avoid the nut from squeezing the inner race too close - it’s not a sophisticated piece of kit. In addition to proper measuring tool for the shim - you also have the back-up of play trial and error…:slight_smile:

xj6 85 Sov Europe (UK/NZ)

(Aristides Balanos) #163

Some food for thought…
There is a debate about end-play vs pre-load.
Generally I am on the pre-load camp, even for front wheel bearings.
Even more so in the case of the fulcrum, it has almost no movement, but on the other hand is getting hammered every time the wheel hits a bump, if there is any end play the rollers will be hitting the racers every time.
So, I think that you might be OK with the .0137 shim, if I am understanding correctly it’s a 0.3mm difference witch will give some pre-load, I would fit it and see how it feels.
I wouldn’t want any play in there, but that’s just me.


(Mark Lee (Pay Pal Patron)) #164

Thank you gentlemen,
I’ve always been on the camp of preload. On my US (domestic cars), I’ve always tightened up the wheel bearings - snug, then back off just enough to get the cotter pin through the hole & castle nut.

I’ll go with the .137 and see how it feels. For any newbies following this thread, I will be putting together a tear down video, showing the removal of carrier, halfshaft brakes, and differential. other than I need to clean up the cage & weld up some holes, I see no need to tear it down any farther.

I suppose while the Diff is exposed I should replace the seals. This too is uncharted territory for me. So I’ll be back with questions.

Thank you as always!

(Mark Lee (Pay Pal Patron)) #165

I kinda forgot about Kirby’s book. I took a look at it and reviewed the whole carrier felt vs seal. I did order seals which should be here today. I’m seriously considering pulling out the felt seal and retaining ring and replace with a proper seal. This begs the question on how to compensate for the difference in thickness and to ensure the fulcrum doesn’t get tweaked while torquing & there isn’t any end play between the fulcrum and the carrier bearings stack of bits

I did read about putting in a bit of bent wire or sheet metal which didn’t really set well with me, I was hoping for a better solution. How did you compensate for the difference?

Thank you again
Oh, and thank you for subscribing to my (youtube) channel.

(Mark Lee (Pay Pal Patron)) #166

Just for clarification, If the shim is to prevent the castle nut from running out of threads, then either essentially any shim as long as it’s thickness is greater than the calculated end play would be fine.

In my case either (the new) 0.136 or the 0.140 shim should be just fine. The 0.137 is the old shim which has all the signs of being spun - it’s not flat by any stretch of the imagination. High spots are 0.142 and the low spots are 0.137. I’d taken the shim to the honing oil stone to see how flat I could make it with out distorting it. I did good; about 0.0005 high spot; either that, or my shaky old man hands.

Also according to Kerby’s book; the thread relief at the end of the input shaft spindle does essentially the same thing. Avoid over stressing the spindle by running out of threads.

One other thing, the Series I book suggests putting a bit “very thin coating about 1/3 of the end of the spindle” of lock-tight on on the spindle.

I’m not 100% on board with this idea. My experience with lock tight, especially when taking it apart has not been good. I have a graveyard coffee can of broken bolts due to lock tite.

Has anyone else used lock tite on the spindle?

(Robin O'Connor) #167

Use the loctite and if you need to remove the nuts again then a bit of heat will destroy the loctite.

(Mark Lee (Pay Pal Patron)) #168

Thank you, good to know. Do you red or blue loc-tite?

(Frank Andersen) #169

The sole purpose of the shim is to get the bearing play correct, Mark…:slight_smile:

The shim abuts the hub - so with the drive shaft in place and tightening the nut; the inner race is unaffected irrespective of torque applied to the castle nut. Play stays at the level set by the shim. Bear in mind that the play measured is the sum of the play of the two bearings…

From your measurements taken, methinks that the ‘0.137’ will give excessive play, but no harm is done by experimenting…

As an aside; ‘end play’ and ‘preload’ both aim to get the correct clearance between the outer and inner races. The first measures axial movement, the other the resistance to turning. Only if specs are given for both methods can either be used…

xj6 85 Sov Europe (UK/NZ)

(Robin O'Connor) #170

I have red thread locker and a green/blue shaft fit that I use when I have a doubt.

(Mark Lee (Pay Pal Patron)) #171

I have two sizes of new shims .136 & .140. According to the Jag Series I manual neither are what I need, based upon the .032 - .004 = actual end play of .028. Less the .150 from the “master spacer” that leaves 0.122. So wouldn’t a thicker shim such as .136 provide less end play?

Bing! On goes the light. In my head… Like you said, the endplay is between the two races, so the smaller the shim the less endplay… I get it. me thinks

(Aristides Balanos) #172


If I remember correctly, the seal does not interfere with the shimming process.
The seal seats in the wishbone and runs on the seal track.

A neat trick I’ve learned at school…
Substitute one shim with electronics’s soldering wire and assemble the shaft.
Keep tightening until you get the desired end-play, or keep tightening until you get no play, and even more if you want pre-load.
Remove the soldering wire and measure it’s thickness, it’s the shim thickness you need.


(Frank Andersen) #173

Me thinks so, too, Mark…:slight_smile:

Measuring and computing is just a shortcut to get it right the first time. With an assortment of shims, or grinding; trial and error ultimately will also give the desired result.

Trick here is that the hub is kept fixed (by the mandrel, ‘master spacer’), while the hub carrier is free to move to measure the play. Trial and error method require another method to ‘lock in’ the hub…

As an aside; the ‘thicker’ shim originally fitted may relate to tolerances in the bearings - but may also imply that the outer rings one the two bearings were not fully seated. As Aristides rightfully say; excessive play allows shock loads on bearings - and also on the shim in this case. Which may or may not explain deformations on the shim…

Spec play is required for the bearings to operate and last - so some attention to this detail is worth while…

xj6 85 Sov Europe (UK/NZ)

xj6 85 Sov Europe (UK/NZ)

(Robin O'Connor) #174

Neat trick if only I’ll be able to remember it when I come to do the rear of the ‘S’ :frowning:

(Mark Lee (Pay Pal Patron)) #175

that is a neat trick!
Like plasti-guage for measuring main and rod bearing tolerances. Cleaver!

(Frank Andersen) #176

That’s not preload, Aristides - on the hub that will be a bearing with excessive play…:slight_smile:

xj6 85 Sov Europe (UK/NZ)

(Andrew Waugh) #177

This is how you measure backlash on really large gearboxes. We used non fluxcore solder, but these were fairly large crane, anchorwinch, and minehoist gearboxes where the teeth were about 4" deep. The lead wire was about 3/16 - 1/4" dia, backlash was in the order of 1/16", iirc.

(Aristides Balanos) #178

Indeed Frank you are right, this method is not intended for setting a Hub,.
The Hub bearings don’t have shims anyway.


(Mark Lee (Pay Pal Patron)) #179

I think i ended up with the “preload camp” I wasn’t making any headway with the shim, I was actually making things worse - to much end play. so I took the mandrel out and decided to put just a bit of preload on the bearing, then adjust with the shim. Well I have .0002 end if any. Now I’m debating whether or not I should take the hub out and start over.

(Mark Lee (Pay Pal Patron)) #180

I did make some headway this evening. I spent about an hour and got the other hub, halfshaft, and brake assembly off. prep’ing for clean up and rebuild.

I purchased the alternative seals to replace the felt if I’m up to ripping out the felt seal retainer. I’m still on the fence on this one. I just can’t get my head around the felt sucking up the water and road grit. However, the one thing I have noticed is the grease in that was originally used is really thin almost like a gear lube.
The grease I used is Lucas Red ‘n’ Tacky, tacky. Not the without style tacky but sticky kind of tacky.

It’s an EP grease multi-purpose grease NLGI #2 with a GC-LB rating. Whatever that means. I picked because of it’s good temperature stability (540F drop point) resistant to acid and alkali as well as rust and corrosion characteristics. I’m wondering if I used the wrong grease since the existing grease is so thin. Maybe it’s a thinner lubricant would be better choice. Or am I over thinking all of this (as usual)

It’s okay to say Mark, you’re over thinking this again.

Thank you all in advance as usual!

(Robin O'Connor) #181

50 years ago there would have been grease grease or grease available (and they would all have been pretty much the same)