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Spitfire Spitfire Gearbox Removal

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Don't quote me without checking with others but I don't think the pilot bearing in a Spit is a press fit. I think they are supposed to be loose. Check the fit of the bearing's OD to the crank hole and the fit of its ID to the input shaft OD. Again, others will have to clarify how tight/loose the pilot bearing is supposed to be.

I've never seen that plate on the Spitfire's I've worked on. Sorry... I'm just not familiar with it.

The unsupported input shaft will have some up/down motion but I don't know how much. I don't think there should be much in/out motion going on. As Wayne said, that may be due to a circlip problem.

There is no easy/good way to separate the old release bearing from the arm. It is pressed onto a hat-shaped piece retained on the throw out-arm. There are little roll pins that secure the pivoting guides for the hat-shaped piece but I have never been able to get those pins out... ever. Instead I use some creative bits of scrap and multi-jaw gear pullers to remove the release bearing... typically in pieces.

To flush the gearbox is little more than draining it. Drain the bulk of the old oil and refit the plug. Fill the gearbox with diesel. Operate the gearbox at low speed by connecting an electric drill to the input shaft. Run the drill for about 30 seconds then stop and select another gear. Repeat until you have gone through all gears including reverse. Orient the gearbox so the drain plug is at the lowest spot, then open the plug and drain for hour or two. Leave the drain open to allow the diesel to drip out.
 
Very helpful, thanks guys!
Just so I am clear, that "c" clip your talking about is in the gearbox correct? I didn't plan on dissembling the gearbox since I have what I believe to be a good replacement. If the replacement turns out to be a dud then I'll have no choice but to tear one of them down.

After some more research, that mystery bracket appears to be a piece of an old exhaust hanger.
 
It has been a while since I worked on a gearbox. From what I remember the input shaft has a bearing pushed in place and secured with a circlip. A small clip holds the bearing to the input shaft and a second, larger clip fits the bearing OD. That larger clip is secured behind the flange of the input boss bolted around the input shaft at the front of the gearbox.

If you don't have a manual yet, this is a good reason to buy one. In the meantime, visit the Spitbits web site and look through Nigel's collection of exploded parts diagrams for the '75 and later single rail gearbox.
https://spitbits.com/1500/1500gearboxinterior75-80.htm
(parts 17-22)

and
https://spitbits.com/1500/1500gearboxexterior75-80.htm
(part 48)
 
Firm, the C clip is on the main shaft and holds the gears in place. If you are not going to take it apart this would only be a information assessment of what may be your problem.

Wayne
 
Firm said:
After some more research, that mystery bracket appears to be a piece of an old exhaust hanger.
Click to expand...
I'm not 100% certain, but I think that bracket attached to the bottom rear of the case (where the tailshaft would bolt on) and served as the front mount of a restraint cable on later cars. I can't find a parts diagram showing the bracket, but I did find one showing the cable.

page98.jpg
 
Andrew, that cable is on the left side and attaches directly to the lowest leftside bellhousing bolt...it's also a bit of an SOB to detach because it's so stiff. My Spit is originally a California car and would have had all the Cali emissions stuff on it, including a big heavy catalytic converter. I believe that piece of bracket I found was a support for a catalytic converter from which my car has long since parted ways.

Back on topic though; today I rebuilt the slave cylinder and put in a big parts order for everything else I need to get the car back together. Confirmed with the seller that he's available Sunday for me to picked the "good used" replacement transmission - it's a 6 hour round trip so I am hoping it's worthwhile.
 
Remember the rules... even though you think the old gearbox is junk, don't throw it out. You never know when you will need a part off of it or want to trade it for something else.

Keep us posted.
 
Will do - I never throw out car stuff! I might offer the old gearbox up for sale/trade since, but I would never throw out good parts.
 
Battled snow squalls and freezing rain for 6 hours (in a work Mazda 6 GT), but made it home with the new trans. Play on the input shaft is very, very minimal up/down and non-existent in/out so I think I may have lucked out with a good box. Came complete with everything (release bearing, lever, speedo cable, slave cylinder) so I'll have a bunch of spare after this job too :smile:

Spent the evening fixing one of my own daily driver's (Firebird) so I'll have to wait to open up the inspection cover on the new trans and see what the insides look like.
 
I just figured I'd close off the thread and thank everyone for the help. This was probably the biggest peice of work I've done on the car to date and it all went off without a hiccup.

I cleaned and inspected the "new" transmission, everything looked to be in great shape. So I just changed the fluid

I had ordered a new pilot bushing, clutch assembly (w/ release bearing) and all the associated hardware. It all arrive last week and this weekend I took to getting the car back together.

I used the clutch lever that came with the new trans and installed all new pins and a new release bearing on it. Then I put the new mounts on the transmission so it was all ready to go back in. Next I put the new pilot bushing into the crankshaft (tight fit, but not a press fit). Next I bolted the flywheel back in place and installed the new clutch using the proper alignment tool. The pressure plate required some coaxing to fit on the dowels, but it went on.

Finally it was time to wrestle the transmission back into the car, with some help from my fiancee and some coaching from my dad (who couldn't lift do to a recent surgery) we got it in place...The sound when the input shaft finally clicked into place was so sweet!

I bolted everything back up including the start and slave cylinder. By the time I had bled the slave cylinder it was dark and snowing outside, but I was too excited to try it out that I couldn't resist. I pulled the car out of the garage, everything working correctly. Out on the road there was no longer any hurtful noises when engine braking :smile: The clutch pedal didn't feel great and shifting was tricky, so I quickly pulled the car back into the garage and re-bled the slave. 10 minutes later it was really snowing, but I pulled the car back out and for a few glorious moments whipped around my neighbourhood through the snow; shifting as smooth as glass and free of any strange noises!

I still need to get most of the interior back in, but I couldn't be happier with the outcome here. I also learnt a lot about the car in the process.
 
Well done Firm. Always good to hear how things turn out and sounds like you did a great job. Oh, you might want to keep the girl friend, I did when she helped me in England 54 years ago.

Wayne
 
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