Seized Spitfire Mk3 speedometer

[Graham C]

Sounds as if the Triumph gods are looking after you.

Going well.

Graham

[Rockape]

On 16/09/2024 at 16:19, DanMi said:

Just an aside, the slave cylinder should have the bleed nipple at the top as air bubbles rise so won't bleed well in that position

Thanks. . I guess the PO did that…another thing to add to the list “while I am here”….

 

still can’t get the extension casing to shift though ☹️

[Rockape]

Speedo update

Well - finally the damaged worm drive is off the shaft. It is not *that* badly damaged, but probably needs replacing.

Once I took note of the tip to fabricate a plate to keep the rear bearing of the gearbox in place, a few good blows got it off…..

And here is the funny part……

It “pinged” off and disappeared with a “tinkle, clang” down past the handbrake.

“No problem” I thought…it will be on the floor…..

Nope - it is on a small ledge of the chassis jua before the diff. Which is where it will stay until I can get the car moving again and onto some ramps!
 

QUESTION…..

Should have paid more attention to the Haynes manual. One of the bolts holding the extension piece is longer than the others. 
 

looking at the gearbox case, some of the threaded holes are blind, others not. 
 

so which one is the longer bolt supposed to go into?

is their a correct torque setting for these?

 

thanks

[Josef]

My memory was they should all be the same, Canley’s agrees https://www.canleyclassics.com/?catalogue=triumph-spitfire-mkiii&diagram=triumph-spitfire-mkiii-gearbox listing 5 x 5/16 x 7/8”. They will have a torque setting, should be in the front of the WSM. 14-16 lb ft in my copy (extension to gearbox is the one)

[Rockape]

1 hour ago, Josef said:

My memory was they should all be the same, Canley’s agrees https://www.canleyclassics.com/?catalogue=triumph-spitfire-mkiii&diagram=triumph-spitfire-mkiii-gearbox listing 5 x 5/16 x 7/8”. They will have a torque setting, should be in the front of the WSM. 14-16 lb ft in my copy (extension to gearbox is the one)

Haynes manual  is at pains to say (at the end of the paragraph that says “remove the bolts”….

 

“make note that one is longer than the others and needs to go back in the same place” !

[Josef]

Huh, that’s odd. I’ve just been through all the parts diagrams for the boxes that use the same (or similar enough) case and they all list HU807 which is a 7/8” bolt for all fixings. The important thing is that nothing protrudes through the case into the inside of the box, and nothing bottoms out in a blind hole though. 

It’s not impossible it’s a Haynes error, they won’t have been taking apart a brand new car after all. How long is your odd one out? 

[johny]

No, its mentions the same in the early Triumph WSM and it must be related to the 3 synchro box which has a different main case. Looks like the longer bolt goes in the bottom left hand hole where it goes right through the casing to be exposed on the other side.

  

[Josef]

Again odd as the parts diagrams I was looking at were for the roundtail Spitfires, and Herald 1200 and 13/60. All three synchro cars as I know we’re talking about a three synchro box here.

[Rockape]

While I am here I may  as well try to get the reversing lights to work….

but where did they hide the switch? 🤔Damned if I can find it!🤷‍♂️

[Pete Lewis]

depends on the age  later the switch was fitted into a threaded drilling in the top cover under the remote hsg.

operated directly by the reverse ward in the top cover .

if early then its on a bracket held on the top cover bolts and operated by a cam on the front of the remote

as is similar to the OD inhibitor ,

 

or  is it a retro fit and has a switch hidden on the dashboard  ???

Pete

Edited September 20 by Pete Lewis

[Josef]

With a three synchro box and a Mk3 Spit then the reversing light switch should be mounted on a bracket similar to the overdrive inhibitor switch. You should have a cam like the one shown here 

at the front most part of your gear change extension. Then a bracket bolted to the top of the gearbox using the same bolts as attach the top cover.

[Rockape]

So essentially picking off the physical position of the stick - not something intrinsic to the box interns? Do I have that right? 
 

i may need to fab my own mount and fit a microswitch.

[Josef]

Yes you’re correct. You can get a glimpse of the brackets at about 4 mins in to this video https://youtu.be/Lk7yQNcV_44 (not the best view but they weren’t what I was trying to film!)

[Rockape]

Question on the rebuild - 2 actually

 

1 when refitting the extension do you remove the old rear seal, fit extension, then fit new seal; or, fit entire assembly, then remove the old seal and fit new one? Or does it not matter? Which is easiest?

2 is there a correct torque setting for the bolts holding the extension onto the gearbox?

thanks

[DanMi]

14-16lb/ft for the bolts. I would think it easier to fit the seal before installing but can be done after

[johny]

Definitely easiest to change seal with extension off the gearbox then put in place all done. Torque values and all instructions are in the free to download workshop manual.....

[DanMi]

I thought that the reverse switch was in the top cover under the extension as can be seen here, maybe it varied 

https://www.ebay.co.uk/itm/285177122731?var=0&mkevt=1&mkcid=1&mkrid=710-53481-19255-0&campid=5339055780&toolid=20006&_ul=gb&gad_source=1&customid=02bb800078f020e1543bc3bb1767060e092f445c

The longer bolt is mentioned in the workshop manual but not where, possibly bottom right as there is an exhaust bracket

[Rockape]

1 hour ago, johny said:

Definitely easiest to change seal with extension off the gearbox then put in place all done. Torque values and all instructions are in the free to download workshop manual.....

Apologies…can you post the link again? Thanks

[johny]

vitessesteve.co.uk and it is a safe site...

[DanMi]

12 minutes ago, johny said:

vitessesteve.co.uk and it is a safe site

There is not one there for the mk3 but the herals/spitfire mk1/2 covers almost everything (bar the engine differences) and the mk3 parts list is there

[johny]

yes got all the important stuff👍

[Josef]

7 hours ago, DanMi said:

I thought that the reverse switch was in the top cover under the extension as can be seen here, maybe it varied 

https://www.ebay.co.uk/itm/285177122731?var=0&mkevt=1&mkcid=1&mkrid=710-53481-19255-0&campid=5339055780&toolid=20006&_ul=gb&gad_source=1&customid=02bb800078f020e1543bc3bb1767060e092f445c

The longer bolt is mentioned in the workshop manual but not where, possibly bottom right as there is an exhaust bracket

Yeah you’re right for the 4 synchro three rail boxes, as fitted to the Spit MKIV, 1300TC etc, or Vitesse and GT6 but with different gear ratios. The three synchro boxes though had external reverse light switches, and the top cover for a 4 synchro box can’t be used on the older style as the reverse throw is slightly different (so I’ve read, I’ve not tried myself).

[DanMi]

16 minutes ago, Josef said:

The three synchro boxes though had external reverse light switches, and the top cover for a 4 synchro box can’t be used on the older style as the reverse throw is slightly different (so I’ve read, I’ve not tried myself).

look at the box in the picture, it has a square flange and is from a mk3 so is 3 synchro  and another clearly mk3 at sideways technology https://sideways-technologies.co.uk/forums/index.php?/topic/9251-mk3-spitfire-engine-and-gearbox-rebuild/

Albeit that is a late mk3 so looks like they were changed at some point

Edited September 21 by DanMi

[DanMi]

yes if you look in the parts manual there was a change to the top cover at FD55620 the reverse actuator was changed. I guess that is the change point

[Josef]

Looks like my parts manual is too old to show that. I did spot that early mark 1/2s had a different third gear though. Both those boxes do look like frankensteins (the sideways technologies one is noted as having a GA prefix case, and the one in the eBay listing is also of an earlier type casting - without ribs). So, not fully conclusive. It would make sense that the method of reverse switch actuation was harmonised with the 6 cylinder cars, so I’m not disagreeing, just am a nerd about these sort of things and like to know stuff for sure!