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Dropping gearbox to replace fork pin, need guide

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Re: Dropping gearbox to replace fork pin, need gu

The first TO bearing sleeve I ordered for my car: I went to install the bearing on the fork, and the 2 "tits" wouldn't fit in the groove. So, I measured the old bearing groove to make sure the fork wasn't made wrong, and it wasn't. So, I took the new sleeve to a local machine shop to have it fixed. I walked in, and there was what I would call a million dollars worth of machinery. So, I told the owner, an older gent, exactly what had to be done. He told me I could pick it up the next day, no problem. So, I went back the next day, and he said to go and pay his wife. So I did. Then I go over to him to get the sleeve. He then tells me he went a little to deep, well,he destroyed it. Only after he has my money does he tell me this. Life goes on, somehow.
 
Re: Dropping gearbox to replace fork pin, need gu

Tinster said:
Randall- The TR4A shaft has the grease zerks on the ends.
Click to expand...
Shouldn't, as I believe they were deleted during the TR4 run. Check your Moss catalog, where it lists the same shaft for TR4 after CT50124 (and TR4A) as it does for TR6.

In any case, my Stags don't have room for the zerks on the end of the shaft, don't know about the TR6.

The later shaft will definitely fit the earlier boxes, but in addition to missing the grease zerks, it also is missing the groove where the locating bolt holds the shaft into the gearbox. But you can simply discard the bolt and let the fork ride against the side of the TOB carrier, like the later boxes do. Also not too hard to add the zerks to the ends of the shaft, if you want (and have room for them). That's what I did when I put the TR6 box in my TR3A.
 
Re: Dropping gearbox to replace fork pin, need gu

Randall:

Here is the Moss Motors TR4A fork shaft
I installed in my TR6. Grease zerks on both ends
plus and alignment/centering groove one the end.

regards,

d

TR4ABar.jpg
 
Re: Dropping gearbox to replace fork pin, need gu

guys, looking at this sachs p.p./koyo t.o. bearing setup from BPNorthwest:

https://www.bpnorthwest.com/.sc/ms/dd/TR250-TR6--Clutch Components/8061/Clutch Kit SACH 4-pc KOYO

according to some, this is pretty similar to the magic clutch setup from trf.

also adding to the purchase order..
fork + fork pin + shaft + bushings
rear engine seal
transmission mount

i may replace the hydraulics as well, the MC looked ancient and the slave might have a slow drip that i noticed when last bleeding the clutch.

are there any glaring omissions?

thanks, steve
 
Re: Dropping gearbox to replace fork pin, need gu

Steve :

Before you start modifying your clutch with non-standard components, you might want to read through this article by Nelson Riedel. It illustrates quite well the problem that many have found with this conversion.

In a nutshell; the original TR6 design called for the bearing to spin all the time. The Koyo bearing is stiffer, meaning it will not reliably spin unless you make other modifications as well. If it doesn't spin and you don't make the mod to pull it back, the bearing face will drag against the pressure plate fingers all the time, leading to rapid wear and in many cases, objectionable noise.

ISTR someone described it as a "stuck pig"
grin.gif
 
Re: Dropping gearbox to replace fork pin, need gu

TR3driver said:
That illustration is Moss 596-051, listed for TR2-TR4 to CT50124 (and, BTW, N/A according to their website)
IOW, that may be the shaft you have, but it's not for a TR4A.
Click to expand...

That's mighty curious, Randal. The drawing I posted is EXACTLY the fork
shaft I purchased and installed- complete with zerks on both ends.

I originally purchased a TR6 shaft from TRF but it had no zerks or
centering groove so I then purchased the "TR4A" shaft.

Oh Well, it works just fine and has zerks on both ends.

regards,

d
 
Re: Dropping gearbox to replace fork pin, need gu

Exactly. That's the problem I have. I know how to get around it, haven't had time to mess with mine, except, I did do a temporary mod for now. I think people are kidding themselves,if they drive enough miles, to think the magic type clutch won't be a problem. However, if you don't drive much, you may be ok. But, on the other hand, they do feel good.
 
Re: Dropping gearbox to replace fork pin, need gu

good points..

maybe i should stick with the borg... i was nervous about the strain being placed on the fork with the stiffer borg, but if i reinforce the fork to the shaft with the 2nd bolt that will minimize that fear.
 
Re: Dropping gearbox to replace fork pin, need gu

Before making a final decision, you might want to read Brent Kiser's clutch article.

He makes a very good point about the B&B plates being sold as replacements being different than the original ones.

The point about the "dowel bolts" is very well taken, too. These are the special 3/8" bolts that serve as alignment pins on the TR6 (and Stag), and are frequently missing or substituted with ordinary 3/8" bolts. The correct bolts have full .375" diameter shanks; while ordinary bolts are always somewhat undersize for easy insertion. The undersize bolts allow the gearbox to slip out of alignment with the crankshaft, which can lead to clutch chatter and drag.

I was able to find a NORS "correct" B&B from eBay when I put the TR6 clutch on my TR3A, along with a standard RHP bearing and TR6 carrier. Worked out great for me, light, easy to modulate and no trouble at all handling the torque. But I opted to keep the original TR3A linkage arrangement, which includes a spring to pull the TOB back from the PP, so I don't know how that part would have worked out with the TR6 arrangement.
 
Re: Dropping gearbox to replace fork pin, need gu

She's done! Haven't given it a proper test drive yet, but I shifted through all gears while on stands (I like living dangerously) and the clutch and nicely engaged/disengaged.

Wish I could be more excited about this, but the fun went out of this job after the first few weekends. The job got drawn out for a variety of reasons (vacation, family birthday parties, work) but mostly it was because I decided to fix a lot of petty annoying things which I had convenient access to (i.e. re-routing the air/heater hoses, replacing tranny seals, re-spray tranny tunnel, new radio, etc.). At times I didn't think it would ever get done. In fact, in retrospect.. I think I may have subconsciously spent too much time on the little things to avoid the big thing: getting the tranny back in the car.

Getting the tranny back in was difficult, and yes I should have enlisted the help of someone to assist. But I decided to go it alone, I was able to manage with one floor jack under the tranny and the other under the engine. Using both together I was able to finally come to a proper alignment of the bellhousing-to-engine plate. The job wouldn't have been possible for me without the use of the homemade 3 inch studs (1/2" bolts with heads sawed off). I place one stud just left to 12 o clock and the other one just to the right. I was also very careful to have the alignment pins in place before the mating. It was a little tricky trying to keep the weight off of the clutch shaft lever when the thing slipped to the left, and I was a little disheartened when I couldn't close the last 1/4" of gap between the bellhouse/engine plate (which I attribute to the tight fit of the alignment pins). To close the final gap, I had to pull the two surfaces together by starting to fasten them together with the dozen or so bolts; I would not breathe easily until I executed the initial clutch test which as you know by now was a success.

So here's my new clutch set up:
New clutch master cyl and slave cyl (both stock bore) with steel braided hose.
DOT 5 fluid.
AP Driveline/Borg Beck clutch pp and disk.
New clutch shaft, fork.
Doubled up on the shaft bearings.
Reinforced the fork to the shaft with 1/4" grade 8 steel thru-bolt, lock washer, nyloc nut.

I went with the AP Driveline clutch because they make the clutch to Bork and Beck specifications, and I justify the Borg and Beck clutch because it was the nearest thing (IMHO) to what was stock on the car originally and it is what came out of my car. Yes, they are a stiff clutch, but I believe that the thru-bolt reinforced clutch shaft fork will be strong enough to handle this.

I would like to thank EVERYONE who contributed to this post. It was really nice going into a big job like this with all the tricks and watch-out-for's that you guys provided.

If any one's looking for me this weekend, i'll be taking a LONG cruise along route 3A.
 
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