Spitfire Spitfire - Rear Hub Bearing & Axle Assembly Steps?

[dklawson]

Thanks to a member here I have a pair of short length Spitfire axles I'm reconditioning for my project car. (There is a fatal problem on the RR axle of our '72).

I have removed the flanges from the axles in anticipation of fitting new rear wheel bearings. I have read through my Haynes, Bentley, and AutoBook manuals. I can't find something in the instructions. While I may understand "why" it's not in there, I want to bounce this off those who have done this before.

The instructions talk about where to position the grease flinger disk on the axle shaft and give detailed instructions on where and how to fit the seals, needle bearing, and ball bearing. What they do NOT say is how far the axle is pressed into/through the inner race of the ball bearing.

I have not pressed the axle out of the bearings yet so I haven't seen the "hidden" portions of the shaft. Am I correct that the shaft does NOT have steps/shoulders and that you need to position the exposed, tapered end of the shaft "about" where it was prior to disassembly? Am I also correct assuming that when you tighten the flange onto the shaft that the axle will be “pulled” through the bearing to the correct position? Thus, the small inboard end of the flange would be resting firmly against the inner race of the bearing.


If I’m wrong, please let me know. If there are controlled assembly dimensions I need to work to, please let me know that as well. Thanks.

 

[tdskip]

Not sure Doug - but asking and having this get documented on the forum for other Spitfire owners is a good thing!

 

[Andrew Mace]

Doug, the earlier factory manual (Herald/Vitesse 6/Spitfire) also says nothing per se about how far the axle is pressed into/through! I'd have to assume it somehow magically takes care of itself if the steps for installing the bearings are followed properly and, ultimately, the nyloc nut is properly torqued (100-110 ft./lb.)?

 

[dklawson]

Thanks guys.

I was thinking that the application of the torque would pull the flange firmly against the inner race of the bearing as the axle/flange tapers seat against each other. But... for that to work consistently I'd think that Triumph/BL would have wanted to specify an initial "press in" depth dimension so too much axle wasn't sticking out beyond the hub.

Perhaps someone will post with a definitive answer while I clean and paint the parts. If not, I'll press to a few thousandths below where things are now and be sure to torque to the proper value.

Andy, while I've got your attention, do you have any helpful hints on removing the rear trunnion bolts if they are frozen when I start taking the old parts off my car? Any advice will be welcome and helpful. Thanks.

 

[Andrew Mace]

Andy, while I've got your attention, do you have any helpful hints on removing the rear trunnion bolts if they are frozen when I start taking the old parts off my car? Any advice will be welcome and helpful. Thanks.

A lot of you may not like what I'm about to say, but I suggest taking it to someone and letting them do that. These can be a giant pain in the, uh, place where pain can be. :wink: On a couple of occasions, I've spent hours trying to cut the bolt, heat up and burn out the bushings and such...all in vain. After one such episode, I took it to a local mechanic who spent a good hour or more doing whatever he did. He got it apart, finally, and apologized for the fact that he was pretty sure I wouldn't be able to reuse the bolt!

Realistically, lots of heat and a hydraulic press might be the way to go. I only have propane torches and no press, so....

 

[dklawson]

Thanks Andy.

If that's what it takes, I do have a hydraulic press at work. If necessary I can always machine off the head and shank of the bolt. The replacement axles came with new bolts so I don't have to work about re-using what's there.

I'm still hoping that I'll get lucky and the bolt won't be frozen to the trunnion spacer tube.

Thanks.

 

[HerronScott]

Doug,

Although we replaced the axles and axle bearings in my wife's 1968 Spitfire back in the 1980s, I never had an answer to this at the time and just let the flange pull it through to what was hopefully the correct final position. I do recall that getting the shaft extracted almost always was a real pain even for the machine shop that had the large presses.

Even though we don't have the Spitfire anymore this would be great information to have for the other Spitfire owners as Tom mentions.

Scott

 

[dklawson]

It was cold and very windy here today but I forced myself to go out and spend a little time on the Spitfire. My intention was to loosen the nuts for the big bolt going through the right rear trunnion and start spraying the joint down with penetrating oil. Much to my delight, when I took the nuts off I was able to tap the bolt to one side using my brass hammer. It appears that I have been lucky and the fasteners back there are not seized.

 

[Andrew Mace]

Yay! :hammer:

 

[billspit]

I have just finished doing this with one set of axles and am about half way through the second set. If you got the hub off without damaging it, you are well ahead of the game.

The grease flinger is the only thing that has a specified distance (146-147mm IIRC). Make sure you have the inside grease seal inserted in the correct direction. It should go in so that it can leak grease to the outside when you pump grease into the hub. This keeps the seals lubes. The reason I tore the axles apart was because of a moaning sound I was getting from the rear end as soon as the car started rolling. I suspect the seals had gotten dry even though I had been pumping in grease over the years. I woke up in a cold sweat this morning thinking I may have put the outer seals in backwards too. I have to go check the factory manual. I do know that they were reassembled the same way the second set of axles were done. This is the third time I've had this set of axles apart and its getting old.

Once you put the inner bearing and seal in place, press the outer bearing into place in the trunnion. Offer up the axle and start pressing it through the trunnion. I didn't have a press, but used a drift and hammer to tap the outer bearing onto the axle. It just seemed to stop on its own. I then put on the hub and tapped it smartly with a brass hammer, placed on the washer and nut and torqued it down.

Yes it has been cold.

 

[hilsideser]

Doug,
I did an axle half shaft last fall, '08. I haven't gotten it <span style="font-style: italic">or the exhaust manifold gasket or the replacement gearbox installed yet</span>...
I hope to get to the barn in the next day or two to clear out some stuff and clean up for placement of the GT6 so I can get semi-serious about it. I'll look for the instructions that came with the hub puller I used.
There's a story there, too.

I had been in touch with Bill Wroope of the Spitfire & GT6 website fame for several months; hounding him to build some more hub pullers, as he was recuperating from a very serious major surgery. He had gotten able enough and feeling good enough to machine a couple more hub pullers, but then sucumbed to his condition and passed on. After contacting his widow, she sold me the last 2 pullers he built. They are held in highest estem in the tool box. (don't know why I bought both of them, just a born horder, I guess).

Bill was dreaming of getting his black Spitfire to Maxton, N.C. "to set a record" with his Spit...he didn't get to make that trip.

I did use his puller, <span style="font-style: italic">operated as designed</span>, flawlessly. I used the impact wrench. The hub just popped off. Was quite easy. I'll post again after I get the instructions located.

 

[guzzul]

Re: Spitfire - Rear Hub Bearing & Axle Assembly St

Doug - I went through the same thinking when I did my axles.

Have a look at thread "Spitfire rear hubs - where to position bearing?", starting at post number #182026, August 23, 2006.

After positioning the hub and torquing as per that thread, my hubs went on just fine, and the flinger wound up just where it should be. The axles are still turning.....

Good luck.

 

[ScottD]

Re: Spitfire - Rear Hub Bearing & Axle Assembly St

When I did my Spitfire rear bearings, I measured from the end of the shaft to the bearings before disassenbly. Upon reassembly, I positioned the grease flinger as per the manual and reassembled the rear hub and torqued to 100 ft/lbs. I then verified the bearings "landed" in the correct position. I came across the recorded distance in a notebook at work not long ago, I shall see if I can find them this week and will post if successful.

Scott

 

[ScottD]

Re: Spitfire - Rear Hub Bearing & Axle Assembly St

WRT the trunnion bolts I had to cut the heads off with an angel grinder and and drift the bolt shank and inner sleeve with a BFH.

Liberal amounts of anti-seize were applied to the new bolts as they were passed through the new inner sleeve in an attempt to prevent; 1 the difficulty of removing in the future. 2. the vast amount of grunting and cursing and 3. the beer required to return to an even state.

Scott

 

[dklawson]

Re: Spitfire - Rear Hub Bearing & Axle Assembly St

Thanks to all for the additional input. I have checked the other thread that Ross mentioned and done some additional searching. I will press the axle back in to approximately the same spot (based on measurements) and assume torquing the flange in place seats all the components in the correct location.

I took the first axle assembly to work today and used the hydraulic press to remove the shaft from the outboard bearing. Prior to taking anything apart I measured from the end of the shaft to the front surface of the outboard bearing's inner race so I will have a reassembly reference dimension to work towards.

Tonight I cleaned all the old parts and examined the new wheel bearing kit from BP Northwest. The kit is from a firm called "Powertune". My reason for bringing this up is, the new outboard ball bearing has seals on both sides and is NOT open like the old bearing I removed. Since the bearing housing has a Zerk fitting hole to lube the bearings and trunnion, I'm thinking I should pull the seals out of the new bearing and leave it open. What do you guys think?

Thanks for the continued input.

 

[ScottD]

Re: Spitfire - Rear Hub Bearing & Axle Assembly St

The bearigs I used for mine had plastic seals which I removed before installing.

I,too,was of the opinion that it would aid with lubrication and I could not see a benefit to leaving the seals.

Scott.

 

[guzzul]

Re: Spitfire - Rear Hub Bearing & Axle Assembly St

The outer bearing should be an open ball bearing (marked LS10 somewhere on the bearing). You're right, it is lubricated through the trunnion/hub so its not clear to me why it would ship with a seal.

Are the 'seals' just a plastic cover as Scott mentions? If so, I would pull them out. I can't see having plastic inside that hub and I would not install a sealed bearing. I'm assuming what you have in the kit is not a true sealed bearing.

If in doubt, call BPNW. They are pretty knowledgeable and helpful.

 

[dklawson]

Re: Spitfire - Rear Hub Bearing & Axle Assembly St

This post is an update simply to assist others who may someday be searching for information on the Spitfire rear axles.

After cleaning and painting all the bits of the rear hub and axle I installed all the bearings and seals per the steps outlined in the manual. I then inserted the axle into the hub and placed a tube over the nose of axle letting one end rest on the inner race of the hub bearing. Once that was in place I put a large flat washer over the other end of the tube and fitted the nut to the axle. I tightened the nut and watched what was going on. Tightening the nut provided more than enough force to pull the axle into the the hub's outer wheel bearing. Once the axle was far enough into the hub I removed my nut, washer and tube and refitted the wheel flange, thrust washer, and nut.

So, the hydraulic press which was very necessary/helpful taking this apart was not necessary for reassembly AND the hub/flange/bearing does find itself at the right point along the axle once the nut is tightened.