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TR4/4A Knurl hole for TR4A wheel studs...

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F1LOCO

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Anybody know the correct diameter of a hole I'm supposed to have to install TR4A wheel studs on the hubs (front and rear) for the knurl? Saw a post saying the knurl is .518 on a TR6, which allegedly are the same as the TR4 and 3? How much wiggle room do I want to press them in to bite correctly? .5"? I'll get one shot at this or I'll be having to get the newer ones from Dorman and ream out to 9/16", but hoping for the best...

On a positive note, Hap is hooking me up with the Silverstone II's that should bolt up when I'm done. :laugh:

Anybody need some EMPI's for a VW? LOL
 
The fronts are the same as the TR6. But on a TR4, the rears are screwed in from the front surface of the hub and then peened over on the back surface to lock them in place.

If you use replacement studs on the rear (i.e Dorman), Dorman provides a specs for hole size, shoulder length, et c.

To replace the rear original studs, you'll likely need to remove the axles with the hubs still pressed on as this method would be much easier than also having to remove the hubs from the axles. Make sure that you keep the shims from each side separate from each other. If you get things mixed up, it will mess up the R&P mesh in the diff. So take notes as you go.

I removed the peening on my rear hubs *axles NOT attached btw* by punching a center then using a large drill (might have been 5/8" IIFC)on my drill press to gently cut away the peening from the surface. Since the tips of a big drill is wide, it will cut the peen rather than drill through. But, take it slow and be cautious not to drill the hub - at all. When you're close, try backing off the lug using two nuts locked together. It might take a little grinding with the edge of a 3" cutoff wheel to remove enough peen so that you can back out the lugs.

And if you're planning on using original method rear studs, the axles have to come out so that you can peen over the backside.. But some have use JBWeld - not me.

To peen I used a dull cold chisel and hammered a pizza slice pattern on the end of the threaded portion of the lug that screwed through to the back of the hub until flattish, just enough to capture the thread in place.

Hope this helps.
 
Thanks. Actually the PO used hex head shoulder bolts! Not even a grade 3 from what I can feel on the heads. Figure they are 7/16 as the nuts are 7/16-20, so the knurled TR4A ones should work, just got to get the knurl hole correct. There are 4 other holes on my hub, and they appear to have faint spline lines, so I am assuming at some point they had them installed with TR4A lugs - I hope. Hopefully they aren't too far stripped or worn and I can pull the new ones through. Otherwise, I will attempt to ream the 7/16" threaded ones to fit the knurl on the TR4A (assuming it's bigger than 7/16). If that fails, I can order the ones from Dorman with the 9/16" knurl and go even a tad bigger in the holes, though from what I hear, I'll have cut them down.

Someone mentioned a seal should be replaced when pulling the 1/2 axle like you suggested? Do we know a part number by chance? Will the locking tabs also need be replaced? Any other bits I should have lined up?
 
F1LOCO said:
Someone mentioned a seal should be replaced when pulling the 1/2 axle like you suggested? Do we know a part number by chance?
Click to expand...
Original 58800, TRF supplies them as GHS185.

Best to replace the lock tabs IMO. If you do reuse them, use Loctite as well. Given how goofed up the hubs are, I would want to check the end play as well.
 
Thanks.

GHS185 is showing I need two - presumably this is one per side? Wasn't sure if I needed 4.

Same thing with locking tabs, showing need 6, so 3 per side or do I need 12?

Got to invest in a manual.
 
GHS185 is 1 per side, 2 per car (typically referred to as # off 2)
lock tabs you will need 3 per side.
 
Good to get a set of new locking tabs, they're cheap enough.

I have a TR4A solid axle, the rear studs are Moss p/n 661-320. They are the same TR3-4A and they are screw-in-peening-type, not knurled.

Lug nut threads are 7/16-20 on all models TR3-TR6.

ISTR that someone once mentioned TR4A IRS (non solid axle) use non-threading rear studs. But TR4A IRS-TR6 also uses a completely different hub.

Now, IF you find that the rear hubs are too buggered up, is the time to swap them out.

Something I wouldn't look forward to doing again. That's why I converted to the Dormans plus they are a little longer which allows more threads for thicker alloys.

Again, hth
 
PeterK said:
Good to get a set of new locking tabs, they're cheap enough.

I have a TR4A solid axle, the rear studs are Moss p/n 661-320. They are the same TR3-4A and they are screw-in-peening-type, not knurled.

Lug nut threads are 7/16-20 on all models TR3-TR6.

ISTR that someone once mentioned TR4A IRS (non solid axle) use non-threading rear studs. But TR4A IRS-TR6 also uses a completely different hub.

Now, IF you find that the rear hubs are too buggered up, is the time to swap them out.

Something I wouldn't look forward to doing again. That's why I converted to the Dormans plus they are a little longer which allows more threads for thicker alloys.

Again, hth
Click to expand...

Eech, when you say "hub" is different on a TR4A, do you mean the fact they are knurled or the fact the hub is "thicker" or dimensionally different?

The Silverstone II's I'll be getting on order are allegedly bolt up to OE studs with lugs provided, and figure the lengths/pitch are the same b/w the 4 and 4A but didn't consider if the hub was any thicker (hence less bolt thread). Otherwise, I should be hopefully able to press the knurled ones in, even if with a little drilling...
 
F1LOCO said:
Thanks, TR3? But assuming 95% is probably the same...
Click to expand...
Oops, sorry. Forgot you were working on a 4A. I've only got a few pages scanned of the 4A SPC as yet.

Although some parts are common, it's much less than 95%. Maybe 10%.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Eech, when you say "hub" is different on a TR4A, do you mean the fact they are knurled or the fact the hub is "thicker" or dimensionally different?[/QUOTE]
The TR4A was available with two different rear suspensions, IRS and solid axle. Practically everything is different between the two arrangements, including the hubs, studs, stub axle, etc.
 
But the main question is the only difference in the rear studs b/w the TR4 and TR4A the fact the TR4 are screwed in from the front and peened, while the TR4A was knurled and pressed in from the rear (ie, is diameter, pitch and length the same b/w the TR4 and TR4A, provided the hubs on the two are the same thickness of course).
 
If you have a TR4A solid axle car the studs do not press in. Only the 4A IRS cars have press in rear hub studs.
Is yours a solid axle or an IRS car?
 
F1LOCO said:
But the main question is the only difference in the rear studs b/w the TR4 and TR4A the fact the TR4 are screwed in from the front and peened, while the TR4A was knurled and pressed in from the rear (ie, is diameter, pitch and length the same b/w the TR4 and TR4A, provided the hubs on the two are the same thickness of course).
Click to expand...
Yes, diameter, pitch and effective length (above the hub surface) are the same; with the caveat that the length is different depending on whether you have the "disc wheel" or "wire wheel" configuration.
 
TR3driver said:
F1LOCO said:
But the main question is the only difference in the rear studs b/w the TR4 and TR4A the fact the TR4 are screwed in from the front and peened, while the TR4A was knurled and pressed in from the rear (ie, is diameter, pitch and length the same b/w the TR4 and TR4A, provided the hubs on the two are the same thickness of course).
Click to expand...
Yes, diameter, pitch and effective length (above the hub surface) are the same; with the caveat that the length is different depending on whether you have the "disc wheel" or "wire wheel" configuration.
Click to expand...

Thanks. That's what I thought. Looking forward to getting her back up and running w/o worrying about a lug snapping off in mid-flight.. :laugh:
 
F1LOCO said:
Anybody know the correct diameter of a hole I'm supposed to have to install TR4A wheel studs on the hubs (front and rear) for the knurl? Saw a post saying the knurl is .518 on a TR6, which allegedly are the same as the TR4 and 3? How much wiggle room do I want to press them in to bite correctly? .5"? I'll get one shot at this or I'll be having to get the newer ones from Dorman and ream out to 9/16", but hoping for the best...

On a positive note, Hap is hooking me up with the Silverstone II's that should bolt up when I'm done. :laugh:

Anybody need some EMPI's for a VW? LOL
Click to expand...


Did anyone ever find what the actual diameter of the Knurl is on the front hub? I know thew studs are 7/16 20 but not able yet to find the knurl spec.
 
Apparently the Knurl on the front studs is 0.520/13.2mm 7/16 UNF Length below head is 41mm for these longer ones to fit VTO/minilite wheels etc. with 5mm spacers.
 
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