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MG TD TF 1500 - Reassembling 1st Gear onto the 1st & 2nd Sliding

I looked at Dave's rebuild and did not see anything so I thought this might help somebody.

My first gear needed replacement, I was trying to put it off but I found the gearbox to bell housing seal was gone so I tore things apart. I found that the 1st and 2nd sliding hub also was worn so I got both from Moss. They arrived today.

Now internal to this pair are 6 springs and 6 balls that retain the gear in a neutral position so it cant slip into gear on its own. Assembling everything requires 6 hands or something.

I went looking for my ring compressor but I could not find it. Last time I remember it was assembling the Buick V6 for my sons 46 CJ@-A. About 14 years ago.

I went down to the hardware store and got a hose clamp of the proper size. This was to allowed me to retain springs and the balls.

I inserted all the 6 springs and put the clamp loosely on the hub. With the clamp just above the cutouts for the balls I dropped the balls in place and they stayed there. I could then slide the clamp up while poking the balls in their holes and then tighten the clamp a bit more. I then inserted the hub into the 1s gear.

Jim B.


JA Benjamin

The balls still stop the hub from going into the gear. More work needs to be done. I moved the hose clamp so it was just below center on the balls and rigged up a compression device using a two plates and a C-Clamp. By applying a little pressure and going all around a poking the balls into their holes (several times) , the gear eventually slid onto the hub.

Not a lot of work really but you need a way to do it.


Jim B.


JA Benjamin

Hose clamp, C-clamp, it doesn't matter. As Norm Abrams says "you can never have to many clamps".

Nice job Jim.
Mort 50TD (1851) Mobius

Jim, I did a similar thing years ago. When the hose clamped balls stopped movement, I backed up a touch, and gently tapped a small nail between the clamp and the ball, pressing it inward enough so the edges cleared. Popped right in. How was the quality of the gears, and did the hub fit on the mainshaft? George
George Butz

How was the quality of the gears, and did the hub fit on the mainshaft? George

To my eyes the gears looked quite nice. While the original hub has a ring turned in the middle breaking the spline into two sections this one did not.

It seems to fit the main shaft just fine

JA Benjamin

Forgot the picture


JA Benjamin

I did mine exactly the same way back in the mid 60's. My only advice is to be sure that you take the clamp out upon completion as it will bring the car to a real sudden stop on the first test drive. (Don't ask me how I know.)
A. R. Todd

good job on the gears..i used a large zip tie but it worked as you described your effort. regards, tom
tom peterson

Jim,

It is on my site under on-going maintenance. I had to replace first gear after I tore it up in a hare and hound rally.

Here is one of the pictures.

warmly,
dave
Dave Braun

probably should post the pic.


Dave Braun

Great minds!


Jim B.
JA Benjamin

Good day all:

I see Moss has reproduced TD: first speed gears, sliding hubs for first and second speed gears and laygears, per his latest flyer.

I don't know if anyone has acquired any of those items, but if so, a sitrep would be greatly appreciated.

Respectfully submitted:
Jack Emdall, TD3191, New Westminster, British Columbia, Canada.

kernow

the ones in my pictures are from Moss. They just came. I will be assembeling the fearbox soon Just now I have an intestinal flue. I need to check how the spacer washer fits first. I will report back soon.

Jim B.
JA Benjamin

I just got back from this years University Motors gearbox seminar and with a little help rebuilt the gearbox in my TD. John Twist has engineered a dummy first gear that allows one to install thier new inner hub in a new first gear in about two minutes... I would recommend that one consider sending their's to University Motors if they find that the job too challenging.
tom crause

I did feel good enough to measure the length of the new Moss sliding gear today,comparing it to the old one. Were the same within 0.00025" about the limit of accuracy of my measuring tool.

The old washer, the one under the C-Clip, should work. Is there a measure of axial play here?

Jim B.
JA Benjamin



I started to put the circlip on the mainshaft and where the cupped washer goes is not where I expected it to go.
I find there is a substantial gap between the sliding gear and the circlip. It was always there (see before picture, the new gear has the same length as the old one).
I seem to have heard of people making a washer to go in this spot.
Should there be such a spacer?

To me, this seems to be a lot of play.

Jim B.



JA Benjamin

In a word " NO " I did this fix last year . Made my problem noticeably worse. After talking to FR Millmore from this site this was his reply. Hi Keith -
From what I can see, the laygear looks quite good, certainly replaced at least one more time than the first gear. The chipping/wear at the engaging end of the teeth is not a real problem. I've seen gears chipped a third of the way back, no problem, but a sign of rough driving or dragging clutch. It is wear of the tooth contours that IS trouble, and I do not see any. As I said, use ball bearings or other accurate round things as gauges, if you have any doubts.
Your old first gear IS a problem, due to that same tooth wear, and may be the entire problem,
HOWEVER:.
I told you that the spacer has no locating effect, and suggested you leave it out. Examining things more closely, it may in fact have a disastrous negative effect, leading to your problem. If there is clearance between the hub and spacer when in first gear, good. It could be .010 or a foot, makes no difference. However, if there is NO clearance, or negative clearance, then the hub could be preloaded against the synchro detent ball/springs, fighting the first gear detent on the shift rail. The overall length of the hub makes no difference; it is the length from the back of the hub to the synchro detent holes that matters. As I said before It is the fork that determines the gear position, and the hub position is determined by the synchro balls from the gear position. BE CERTAIN that there is definite clearance between the back end of the hub and the bearing bits WHEN it is in first gear. This must be enough that any slop in the mainshaft bearings cannot reduce it to less than zero. If the clearance is negative under either steady state or dynamic conditions, the synchro balls will be pushing it OUT of gear while the rail detent attempts to KEEP IT IN GEAR.
This is where we started, and I repeat <<<LEAVE the spacer OUT>>>

The only other things that affect the issue are the state of the shift fork - bent or loose. Bent will cause the gear to misalign with the laygear, but should be obvious. Loose in the groove shouldn't matter much within reason,
IF the gears are good. Loose on the rail could cause it to not go all the way into gear, which would cause it to jump out easily.
OR the condition of the first gear detent on the shift rail. This includes spring load as assembled, and condition of the detent notch. These notches can be touchy, as can modifications to them. The only check is to know the force required to move the rail out of the various detent positions. As far as I know there are no specs anywhere for this, it being a matter of "sufficient". I can judge by looking at the notches. Compare to the other detents, by eye and by feel when shifting (both into and out of gear). Maybe send me a really clear pic of the notches for this. And remind me where the "extra" spring/ball went.
Might help if Quantum or somebody has real specs for the detent spring load/length. This can be corrected or modified with the gearbox in the car, just remove the cover.

Best.
FRM
I hope this is of some use to you and Fletcher does not mind my reproducing his email. I put a new first gear in from Quantum Engineering now Moss has them.Mind you the gear box is going back together today so I have not personally tested the results. But will try to post back in a month or so when the new pistons and roller cam are all back in ol'Betsy.
Cheers, Keith
Keith McKenzie

Thanks, I will move on.

Jim B.
JA Benjamin

Reactivated. Bud
Bud Krueger

Thanks Bud

Jud
J K Chapin

This is the BMC tool for assembling MGB gears. There was a similar tool for Sprites and midgets, and probably for T-types, too.

Basically, the tool slides over the hub, much like your hose clamp, but there is a hole in the tool. You line up the hole with one of the holes in the hub, insert the spring and ball, then rotate the tool to the next spring hole.

Alternatively, you can clamp the tool in your vice, using the tab, and rotate the gear shaft instead.

Pretty simple to make, if you can find a suitable diameter tube.

When assembling Midget (not T-type) gears, I've always used fingers, but there are only three balls, so it's a bit easier.



Dave O'Neill 2

Got to tell this story. Around 1970 a friend of mine had got to the point of assembling his TF gearbox after fitting sundry new bits. He didn't know about these ingenious techniques, so was stuck refitting the gears until he had a bright idea while his fiancee and her parents were visiting for lunch. Three visitors equals six forefingers!

After lunch he took them out to the garage, set the mainshaft vertical in the vice and, against a certain amount of resistance, persuaded fiancee etc. to push in two oily synchro balls each. One quick swipe with a hammer and all done!

Except that fingers are ductile and their tips go some way into the hole, after the ball. He not only had three loudly complaining future relatives jumping around the garage spraying blood from both hands, but when all the drama was over he had to take the mainshaft apart again to clear all the bits of skin and flesh out.

Don't think that engagement ever worked out.

David
D A Provan

Here is the specific synchromesh assembly tool shown in the TD/TF workshop manual.

John




J Scragg

Thank you J. Scragg for the invaluable image of MG Tool T. 109. Of course, we don’t have a Tool T. 109 but Peter is a better than average welder and thus came into existence the DeJong Ball and Spring Compressor. With this marvelous device we were able to quickly and bloodlessly reinstall the balls and springs and get the sliding hub back where is belongs. This tool is available to any crazy person on the forum who decides against all wise advice to remove the sliding hub from the 1st/2nd gear. If you are thinking about doing this, leave the garage, sit down, have a drink and rethink your plan but the tool is available for the cost of postage to and from Landrum, SC, USA.

Jud






J K Chapin

This thread was discussed between 05/03/2012 and 20/03/2020

MG TD TF 1500 index

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