What are we recommending for a throw out bearing?

[tdskip]

Hi guys - decided to try the spare A-type OD in the '66 TR4a while the other one is being rebuilt. Supposedly it is a good gearbox, we'll see.

The throw out bearing that was on it doesn't spin as smoothly as I'd like, so now is the time to replace it.

I know this has been a subject of much debate / angst - what throw out bearing and source are we recommending these days?

 

[TR3driver]

FWIW I've been running an ordinary original style replacement bearing from TRF since about 2000 or so (when I put a 4A clutch in my TR3A, now moved to the TR3). Works perfectly for me.

But of course, things could have changed by now. YMMV

 

[tdskip]

Hi Randall - hope you are doing well.

Are the bronze shafts a good idea?

How do you tell if your existing sleeve is worn? Or good practice to replace as a matter of practice.

 

[Brosky]

Tom the bronze sleeve is good with Koyo or original bearing. Gunst is bad.

 

[tdskip]

So Moss or BPNW ones OK then?

 

[Brosky]

I didn't know they had them. I was talking about the HD TRF bronze sleeve.

 

[tdskip]

Ah, OK Paul. Thanks.

 

[TR3driver]

Are the bronze shafts a good idea?

How do you tell if your existing sleeve is worn? Or good practice to replace as a matter of practice.

Beats me. I had to change the sleeve when I switched to the 4A clutch, but I just used a standard steel sleeve (AFAIK the bronze ones were not available yet at the time) and it seems to work fine for me. Before that, I just kept reusing the original sleeve.

You might want to read Nelson's article at https://www.buckeyetriumphs.org/technical/clutch/ReliableClutch/ReliableClutch.htm

In it, you'll find his opinions on which TOB is best, along with some things to watch for with the sleeve.

Some things I would suggest:
1) Replace the bushings for the clutch shaft with P/N 36998 (which is the wider brass bushing from a TR3). You may want to replace the shaft as well if it is worn.

2) Add some grease zerks so you can give the bushings a shot of grease once in awhile. On the 3, I added zerks to the shaft (which were original on the TR3 shaft). But on the Stag there wasn't room for zerks on the end of the shaft, so I put them into the gearbox instead (along with a hole through the bushing.

3) Don't forget to reinforce the taper pin, if it hasn't already been done.

 

[tdskip]

How are #36998 fitted? Drive out the old shaft and press them on?

Looks like you have to drill to create a fitting, no?

Any tips on getting the old bearing off?

Thanks.

 

[poolboy]

This anti rotation pin is supposed to be a good idea.

 

[TR3driver]

The shaft should just slip out (TR3 has a locating pin that gets removed first). I made up a mandrel to help in driving the bushings in/out, but with care it can be done with a drift & hammer. (Similar to wheel bearing cups, tap on one side and then the other.)

Yeah, to add the zerk I drilled & tapped. 1/4-28 I think it was.

Come to think of it, I don't recall ever removing a TOB from its sleeve. Today I'd just throw it in the press, but before I had such luxuries I would have used the hammer & drift method. (Obviously not if you think you might try to reuse the bearing, though.)

To install the new TOB on the new sleeve, I used a length of threaded rod, nuts and a pair of flat plates to pull them together. Someone, I forget who offhand, recommends this as a way to avoid damaging the bearing (since the bearing turns as you tighten the nut). I think TRF even sells the rod & plates (RFT121).

 

[tdskip]

Cool - haven't really dealt with any of this other than replacing the bearing/shaft as an assembled unit before. Good to learn, hope this also helps future TR-ians via search as well.

The bearing is most certainly toast, so no worries there. On reassembly I read shaft in the freezer and bearing in a warm place to ease fitting....

 

[tdskip]

BTW - while I'm in there....

I see signs of oil leaking from the center of the bellhousing where the front cover seats.

Can I change the gasket (#56) and seal (#57) without having to take lots apart?

 

[TR3driver]

Can I change the gasket (#56) and seal (#57) without having to take lots apart?

Yup. With the TOB & shaft out of the way, just undo the 4 bolts and remove the front cover. Only caution is to avoid getting crud into the bearing when you are cleaning up the surface where the gasket sits. Wouldn't hurt to wrap some electrical tape or masking tape around the splines, so there's no chance of damaging the seal on installation, but be sure to get them clean afterwards.

The bolts go through the case, so use something to seal them to the cover. I think the factory originally used lead wire, but copper washers and RTV (applied sparingly to the threads just under the head) seem to work for me.

 

[tdskip]

Thanks Randall

 

[tdskip]

Quick question - is a pressure washer too aggressive to clean up the gunk inside the bellhousing. I'm thinking that would save a lot of time but if the oil is capable of leaking out of that seal then a pressure washer would push water in as well?

 

[SMGoose]

Hi tdskip,
I just came across this thread and was wandering what you ended up choosing for the bearing. I'm currently in the process of putting a rebuilt transmission in my TR4 and am considering doing something similar (keeping the brass sleeve and fitting a new release bearing). It'd be helpful to know how it worked for you because I'm straddling the line of budget vs wanting never to do this again! Plus I'm worried about all the nightmare stories of new clutch components not being as good as the old. Thanks.

 

[sail]

Scott, my take on this 5 years ago was get stock throwout bearing. I got this https://trf.zeni.net/TR4-GB/59.php, RFK747. I would not have replaced the original pressure plate from what I have since read. Maybe post a couple pict's of yours in new thread for opinions. New disc's seem less of an issue from what I can tell.
The other thing you want to look at is the taper pin holding the fork to the shaft that operates the bearing. Most add an additional bolt. Mine was broken but drove fine. There are several threads on this, I didn't see the one I wanted just now.

 

[sail]

Pressure Plate Info: https://www.mntriumphs.org/aOLD/Tech_Info/Clutch%20Folder/clutch.pdf

Fork Taper Pin Info: https://www.buckeyetriumphs.org/technical/clutch/ClutchShaft/ClutchShaft.htm

 

[SMGoose]

Thanks, Richard! I made my order this morning just before your response. I had checked out both of those links before, though, and decided to keep the original Borg and Beck pressure plate but buy a new release bearing to put on the old brass sleeve and also a new clutch disc. Here are a couple photos of the bearing and pp:


The bearing was a bit gritty in its movement, but the sleeve looked good and felt smooth. That article you referenced is the main reason I decided to keep the pressure plate. It's the old kind and after cleaning it up, it doesn't look too worn to me.

The clutch system wasn't really a problem before, which is amazing to me now having taken it apart. There were no bushings for the operating shaft and the grease fittings were missing. Needless to say, it was very difficult to rotate by hand. The guy I bought the new gearbox from threw in a new shaft and fork, but somehow I misplaced them. Doh! I cleaned up the old one, though, and bought grease fittings for it. The taper pin was fine, but I think I might do the cross-drilling thing, too, while I'm at it.