TCS Rear Suspension Troubleshooting

[Driver1081]

Hi,

I’m new to this site, but I have had a 74 TCS for about 12 years.  It’s got 73K on it now.  I bought it at 67K and put about 500 miles per year on it.  It’s been ultra reliable for me, until this past summer.  Around May, I noticed a bit of coolant seeping out between the base of the head and block.  I checked the headbolts and they were tight, problem wasn’t excessive, so I decided to run it through the summer and change head gasket in winter.  Next and more exciting, I was driving down the highway at 60mph and 3 of the 4 lug studs broke off the right rear tire.  I pulled over immediately and got VERY lucky that the wheel never touched the body and the car was not hurt.  The wheel hula hooped around the rear brake rotor.  Mine has Miata rear brakes on it.  I changed the studs and all was fine.  The last week in October, I decided to take the car out for a last run of the year.  While playing on a back road, I heard a clunk, then could sway the tail of the car all over the place with the gas pedal.  I limped it home and have now just started disassembling.  The left rear hub splines are completely rounded off.  It has ¼” of play side to side and twists about 15 degrees on the hub shaft.  The retaining nut was tight when I had checked it the end of last summer and the washer was crimped over the hex to lock it.  When I disassembled, the washer was still crimped over, but the nut was only finger tight.  I can’t see a way for the nut to loosen since it’s held by that washer.  The washer has a flat in it which engages the hub shaft and prevents spinning.  Any thoughts on how that happened?
 
Also, I got the hub off, but now need to remove the hub shaft from the carrier.  The manual shows a threaded puller being used, but isn’t very clear on how that is placed on the back side of the hub.  Do most people undertaking this make a piece to attach to a puller on the back side or is there a special puller commercially available to do this?  My other thought is removing the trailing arm and trying to put the whole assembly into a press and push it out?  I’m thinking a change of both sides of rear wheel bearings and U-Joints is smart, even though they seem fine.  Any other ideas recommendations while all is apart?  Any advice is greatly appreciated. 

Thanks,
Peter

[cal44]

Peter,
since you are in the same state as R.D Enterprises I would call him and ask if he carries the shaft removal tool.  May make your life a bunch easier, that is if he has it.  His website is pretty useful.

http://www.rdent.com/

[jbcollier]

You're in the US so Habor Freight can provide inexpensive pullers and bearing splitters.  Use a bearing splitter behind the flange and bolts to attach to a puller.  The you need to use some heat on the flange as it is glued on with a special assembly compound (Loc-tite 635 off the top of my head).  Get the hardened spacers that Ray sells as yours will be toast.

[Brian]

Hello Peter:  I would suggest that the "bearing spacer" within the carrier has been worn out of spec and is the cause of your failure.  The spacer length for a TCS should be 2" plus or minus a couple of thou (can't recall exactly but can get back to you once I check my notes).  There are differing opinions about replacing the OEM spacer with hardened ones, I can only say that with 70K miles on mine, they were still within spec so I kept 'em.  If you really intend to thrash your car about, probably hardened replacements are the way to go.  By all means figure to replace the u-joints and bearings in the assembly.  The parts are inexpensive and easy to come by.  In my experience, removing the hub from the stub axle was the most difficult part of the repair.  It took a lot of heat to break down the locktite holding the hub onto the stub axle.  In order to remove the stub axle from the carrier,  I employed the "temperature differential" method.  Basically remove the half shaft from the stub axle and put the carrier/stub axle in your freezer overnight or pack it in a bucket of dry ice to get it as cold as possible.  Heat up a bucket full of boiling water.  Place the "frozen" carrier assembly in the water and leave it for a couple of minutes.   With a little luck, you will probably be able to tap the stub axle out of the carrier with a hammer.  I'm certainly no expert regarding this method, however, it worked great for me.  Best of luck with the repair.
Another Brian
'73 TCS 3402R

[EuropaTC]

Hi Peter,

Whenever I've done any work on the rear hub carrier I've taken the unit off the car and pressed the bearings in place with a vice. By disconnecting the driveshaft yoke at the gearbox end (a roll pin that you punch out) it makes it much easier to get the outboard shaft free from the bearings. I think the last time I did it the inboard bearing came out on the shaft ?

I reckon the key element in that failure is the absence of Loctite retaining "goo" on the splines between the hub and shaft. I can't stress enough just how critical that aspect of the rebuild is, in fact I use Loctite on the bearing housing, splines and even under the spacer between the outboard bearing and hub. It makes removal a pain for sure and you need blowlamp heat to break it down, but it stays fast and secure until the bearings fail.

The good news is that bearings and joints are quite cheap and I would suggest you replace the whole lot, in fact if you didn't find the Loctite present then as a matter of course I'd do both sides of the car.

I'm on the fence as far as hardened spacers go. I replaced mine back in the 80s and they've withstood several changes of bearings over the years without any noticeable deterioration. It's a mild steel tube in axial compression which you aren't going to squash by hand no matter how much leverage you put on that socket (unless you're the Hulk    ) and so if it shows any wear then it's been loose. (back to the comment on Loctite) 

If I had a hardened spacer on the bench next to a mild steel one then yes, I'd fit it, but I wouldn't go out of my way to find one. 

Brian

edit to add - shucks, where's my manners, I should have started out with a ....       It's good to get long term owners on board.

[Driver1081]

Thank you very much.  It took a while for my Harbor Freight gear puller to arrive due to all the snow delivery delays, but I finally got it.  Even using that with heat, it took me 6 tries to get the shaft out.  It was really stuck.  It's now out and that's what matters.  It took heat, heat and more heat.  On another day I'll start to troubleshoot what I took apart. 

Thanks Again.
Peter

[EuropaTC]

Hi Peter,

That's progress, at least now you'll be able to find the cause.  If it took so much effort to pull apart then I think my previous theory on "no loctite" is wrong because although you do need some heat from a torch, it's not so bad.  I searched through my files and found some pictures of mine from a previous session, when it had drum brakes on. The first shows the puller I used, the second the axle immediately after the hub came off, complete with white, degraded loctite still on the splines. If yours looked like that, then my previous theory is wrong and we need a better one !

When you start the detective trail, post up some pictures of what you find - none of us want our rear wheels falling off 

Brian