Triumph Spitfire 1500 gearbox mainshaft rear bearing

Hi all. Spitfire 1500 (o/drive) gearbox strip down.

Got to the stage of removing rear mainshaft bearing from gearbox casing. Haynes Manual states 'special extractor, but..........use of 2 screwdrivers behind rear circlip to rear bearing, and tapping end of mainshaft with soft hammer....etc.

Tried the screwdriver / tapping exercise, but with no joy. The bearing will move out of the gearbox casing (slightly), but is dog tight fit on the mainshaft.

Anyone any idea on how to free the rear bearing along the mainshaft? ) note - small rear circlip and thrust washer has been removed.

Regards, Tom

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Reply to
Tom Sharrocks
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If you put a picture up somewhere it might jog some memories, somewhere.

Reply to
mrcheerful

Struggling to remember what I did... I'm pretty sure I had to pull out the layshaft and drop the laygear into the bottom of the gearbox first. Then by pushing out the input shaft bearing (removing the input shaft?) I got enough clearance to push the mainshaft through its bearing by tapping its outer end. Does that sound right?

Reply to
Willy Eckerslyke

: Anyone any idea on how to free the rear bearing along the mainshaft?

The first working method I tried was supporting the bearing on a stout metal plate with a hole for the shaft and belting the bejabers out of it with a hammer. Which rather neatly belled the end of the shaft. So don't try that!

Ian

Reply to
Ian Johnston

Willy,

Sounds like we are in the right street.

The rear mainshaft bearing is still installed within the gearbox casing, with the mainshaft and gears still in place. I have dropped the layshaft into bottom of gearcase and removed the input shaft. Also removed the reverse gear shaft.

I had another go last night to free the rear mainshaft bearing, but it is stuck rigid to the mainshaft. The rear mainshaft bearing will move approx 3 mm out of the gearcase, but because the mainshaft is tight this just moves with bearing. Obviously the gear cogs on the mainshaft just jam up against the rear of the gearcase becoming 'chock a block'. I have no intention of messing up the end of the mainshaft by over hammering.

The only thing I can think of is to make a bearing withdrawal tool that will mount onto the rear outboard end of the mainshaft, that will engage under the mainshaft bearing large circlip, to assist pulling the bearing up and off the mainshaft.

Welcome any other offers - just wonder what the special tool is, that is mentioned in Haynes manual, for removing this particular bearing?? Only other option is to take to local garage and see what they have available?

Regards,

Tom

Reply to
Tom Sharrocks

with the input shaft gone, can you not remove the rear circlip and pass the whole lot forward?

The sort of tool that will pull a bearing blind is available at enormous expense from bearing shops, it has special flattened balls on extractor arms that are inserted and twisted in the bearing tracks (like adding a ball with a rod on it into the bearing) the bearing is destroyed (by the by).

mrcheerful

Reply to
mrcheerful

Ah, I expect that's where we differ then. I can't remember how much of a wallop I gave mine, but I do keep a 4lb hammer handy. What I probably did, was hold a piece of my leather belt against the end of the mainshaft to protect it, then gave it a clout with the big hammer while taking care to swing the hammer directly in line with the shaft. I don't remember it struggling that much.

Obviously the bearing needs renewing afterwards.

Reply to
Willy Eckerslyke

Gents,

Had another go tonight and success !!!

Based on Willy's experience, used a heavy lead hammer, and based partially on mrcheerful's advice, tapped (quite heavy taps needed) and knocked the mainshaft into the gearcase (although with the outer bearing circlip still in place). Managed to move the mainshaft through the bearing and into the gearcase approx 20mm. I then managed to free the bearing out of the gearcase. With the gear train wired up, I stood the gearbox on end (bell housing end down). With the freed outer mainshaft bearing resting on the gearcase, I continued to tap the outer end of the mainshaft through the bearing approx another 10mm and this loosened the bearing sufficient to pull it up and off the mainshaft..........phew!

With the mainshaft removed, I then removed the layshaft (I had made up and previously installed a hardwood dummy layshaft ) which worked quite well.

All now revealed:- Problem with geartrain - as expected - 3rd gear circlip broken, but only managed to find the half left in the geartrain? Layshaft - 2nd cog from rear has two fairly bad snipped teeth - looks like a replacement required.. At face value, everything else appears ok. The inner and outer main bearings will need replacing. Layshaft needle bearings look worn, so will need replacing, and the needle bearing cluster to spigot / input shaft looks a bit worn. I guess the 3rd gear circlip has perished and a part of it must have dropped into the layshaft train, hence damaged teeth. The magnetic oil drain plug showed a snip off a cog tooth and a pile of filings!

So, thanks to all for your advice on this one.

I intend going on Holiday in North Yorks first week in September, so have installed my 4 speed box into the Spit over the weekend to put me on for now. Will play with the overdrive / gearbox at leisure. A new layshaft will probably be the highest cost, so will do the rounds see what I can pick up............any offers?

Further query, has anyone used this supplier? - Autogear Transmissions

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- price of parts seem more reasonable than otherTriumph dealers?

Regards to all, Tom

Reply to
Tom Sharrocks

That's a relief, I was starting to worry that I hadn't added enough of a disclaimer to my previous post!

David (?) from Canley Classics told me they fit a modification here to allow for larger bearings. I'm not sure how, unless they machine out the input shaft, which would be a job and a half.

One of the Dolomite 1850 boxes I stripped had what looked like a brand new laygear cluster in it - until I saw where the bearings where supposed to go. All that was left was a jagged hole with not a bearing in site. If you can find someone to machine it out for larger bearings you can have it for the price of the postage. I suspect it'd be cheaper to buy a new one though

Reply to
Willy Eckerslyke

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