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View Full Version : TR6 Proper way to adjust front hubs, TR6?



crj7driver
06-28-2007, 09:39 AM
I just put on new front hubs on my 6 and have a question. The book says to tighten the castle nut to 5 ft/lbs and then back it off to align the next available cotter pin hole. It also says to allow .003 to .005 end float.

This allows a little slop in the bearings, when I was a bike mechanic and would adust hubs you wanted no play, but also no binding or grinding sensation caused by the bearings being to tight. If the bearings were to loose the slop would cause the bearing races to be damaged by the free play in the bearings.

If I adjust it the way they say, 5lbs of torque I can almost un-screw the nut with my fingers (I don't remember how "loose" it was when I removed them). Should I try not backing the nut off and seeing if I get any float once the wheel is on and I have more leverage?

Just curious what is normal/right, since this is my first set of car hubs that I am adjusting.

prb51
06-28-2007, 09:51 AM
Yea, I just did mine the other day and felt the same way. When I disassembled the unit (which was working perfectly) I undid the nut with my fingers as it's simply loose and retained by the cotter pin.
For TR3's its a 10 ft lb tighten and then back off 1 1/2 flats (as per manual) which basically means it's loose and there is end float.
Works but you'd think not. Follow the specs.

tomshobby
06-28-2007, 10:06 AM
I have packed and replaced a lot of bearings over the years in vehicles including cars, military vehicles of all sizes, trailers, and farm equipment.

I was taught and used what the book says. If they are too tight they will get hot and destroy themselves. These are tapered roller bearings and a world of difference from ball bearing bicycle bearings.

The slight tightening of the bearings insures they are seated and the backing off ensures they will not over heat.

Also, only the grease in the bearings does any good. Filling the hub will also cause heating. I did use a thin coat in the hubs to prevent corrosion but that was all.

One of the most common causes of bearing failure I encountered was due to corrosion (rust) on the bearing components. This was very common in military trailers (old maintainence platoon sgt.). Not because the bearings were any different but because often times the trailers were not used for extended lengths of time. The volatile solvents in the grease would evaporate leaving cracks in the hardened grease that exposed the races and rollers. Just the moisture in the atmosphere was enough to rust these parts and the slight pitting was enough to destroy the bearings in a short distance, sometimes 100 miles or so.

We began a practice of "exercising" the trailers in our company for a few miles at least once a month and it had a huge impact in the life of these trailer bearings.

In other words, it might be a good idea to turn the wheels on our cars from time to time over the winter storage period.

TR3driver
06-28-2007, 10:49 AM
The book says to tighten the castle nut to 5 ft/lbs and then back it off to align the next available cotter pin hole. It also says to allow .003 to .005 end float.
Does it also mention that you need to do this without the felt seal installed ? There has been a rash of oversize felts recently, which can upset the measurement and result in too-loose bearings. Best practice when installing a new felt seal (in one of the Triumph manuals but I forget which one offhand) is to perform the above procedure before installing the felt; mark the position of the nut, install the felt, then put the nut back at the marked position. A "Sharpie" permanent marker will do to mark the nut & axle if you don't like the traditional center punch method.

when I was a bike mechanic and would adust hubs you wanted no play
The difference is that your bike hubs didn't get hot. But your TR6 hubs have brake discs bolted to them, and the brake discs can get very hot. The clearance is to ensure the bearings don't get overloaded when the hubs get hot and expand.

If I adjust it the way they say, 5lbs of torque I can almost un-screw the nut with my fingers
When it's adjusted right (don't forget to back off at least 1/2 flat), you can unscrew the nut with your fingers. Because of the clearance, there will be no torque on the nut at all.

BTW, this is standard for all RWD cars. My Buick takes essentially the same procedure.

TR3driver
06-28-2007, 11:05 AM
For TR3's its a 10 ft lb tighten and then back off 1 1/2 flats (as per manual) which basically means it's loose and there is end float.
That's a very early specification. It was later amended to 1 flat (Practical Hints 2nd edition) then to 1/2 flat (4th ed I think, but I can only find 6th at the moment).

crj7driver
06-28-2007, 11:30 AM
That is why I love this forum. Thanks for all the input, I can now put the dust seals on and feel comfortable. Btw, I am running Southwick Machine & Design aluminum hubs and they use a "modern" rubber type seal, so there is no felt to contend with. Thank you for all of your quick responses.

prb51
06-28-2007, 03:14 PM
I looked in my 87 copy manual (Haynes) and it had the same 10 ft lbs and back off.
If I had new bearings I'd tighten as directed in the "practical hints edition" listed above but I'd be leary of doing that with bearings that have run in already with the end play as per the original instructions.

TR3driver
06-28-2007, 05:22 PM
Just to be clear, Haynes is an aftermarket repair manual, not published by the factory and known to have many errors in it. "Practical Hints" was written by Standard-Triumph, and included with every new TR2-3 (except for the first edition, which was titled "Driver's Instruction Manual" or something like that, but had the same ST part number).

If your front wheel bearings have "run in" enough to detect in any fashion, then you should replace them immediately ! These are precision roller bearings and are extremely hard, not like the soft bearings found in other places. Even a light matte appearance on the outer races is reason enough to replace them, IMO.

Bearing failures are no fun at all.

TRTEL
06-28-2007, 08:02 PM
If you're into autocrossing, etc. aim for the low end of the clearance range. We used to set up the TR3 racecar per instructions until the bit on the # of flats. Instead we had a selection of hubnuts and kept changing until we had about .002 or .003 clearance using a feeler gauge and gaining ideal hole/slot alignment. Finishing with a large enough cotter pin that the nut would not move. The whole process was obviously to avoid additional knockback to the caliper pistons, which always added to the thrill of having to stand on the brakes after the last hairpin.

txtr3
06-28-2007, 08:53 PM
Forgive the novice question, where/how do you measure this with a feeler gauge?

Thanks,
Jiri

Greg_Blake
06-28-2007, 09:19 PM
If you are running the Southwick hubs, are you also using their stub axles? If you are, do not use the methods suggested above. Send me a PM if you have the Southwick stub axles.

Greg

Brosky
06-28-2007, 09:40 PM
Love the color, by he way!

TR3driver
06-28-2007, 10:19 PM
The stock axles are 20 tpi, so 1/2 flat is about .004"

You'll get more improvement in the knock-back by installing the uprated stub axles and spacers that Greg is talking about.

(TS39781LO took 1st in class at the VTR 2000 Auto-X.)

TRTEL
06-28-2007, 10:38 PM
Between the 'D' washer and the inner bearing race. Just use your fingers to tighten the castellated nut until you feel a light drag on the feeler gage. Always use a small torque wrench (3/8 or 1/4) for the initial 10 ft lb setting, trying to read 10 on a big one (0-150)is always off.

PS Just read the last post and yes the uprated axles are the way to go. Of course none of that was allowed circa 1970.