Speedo gearbox, back axle T140v

[Magno]

Hello Bikers
I have a back axle problem. The speedo gearbox on the right side is rubbing and wearing against the rear brake disc. I've taken apart the back axle assembly and it looks to me as if there should be a spacer or washer between the gearbox and the disc. Am I right in thinking there is a missing spacer or is there another way to lift the speedo gearbox away from the disc?
Any help much appreciated.
Cheers

 

[Rocky]

I think you may be right. I had a similar situation when I bought my 1970 T100S.
I don't have an answer for you, but I fitted a spacer of some sort (it was 20 years ago) and that solved the problem.
Do you have a parts book? That should show a spacer if there is one.

 

[Magno]

I think you may be right. I had a similar situation when I bought my 1970 T100S.
I don't have an answer for you, but I fitted a spacer of some sort (it was 20 years ago) and that solved the problem.
Do you have a parts book? That should show a spacer if there is one.

Many thanks Rocky,
I do have a workshop manual but it doesn't show a spacer. I just called my supplier in N England and he is posting me something that I hope will do the job.
Weather's great here and there's no time to lose.

 

[Rocky]

That's good news. I hope it works

 

[Rudie]

I do have a workshop manual but it doesn't show a spacer.

If you use the correct Triumph workshop manual for a T140V with a rear disc brake - 1976-1978 - it does, manual Section F14, page F21 is a full-page drawing of all the rear wheel components, the spacer is shown next to the speedo drive.

supplier in N England and he is posting me something that I hope will do the job.

You would help yourself more if you used a parts manual as well (e.g. free to read online at British Only Tech Library?). Not only is the same drawing there, all parts are numbered and listed on a parts manual's following page; in this case, the spacer is "12 37-7021 Washer - speedometer drive gearbox".

The Washer/spacer looks and fits like this:-

 

[Magno]

If you use the correct Triumph workshop manual for a T140V with a rear disc brake - 1976-1978 - it does, manual Section F14, page F21 is a full-page drawing of all the rear wheel components, the spacer is shown next to the speedo drive.


You would help yourself more if you used a parts manual as well (e.g. free to read online at British Only Tech Library?). Not only is the same drawing there, all parts are numbered and listed on a parts manual's following page; in this case, the spacer is "12 37-7021 Washer - speedometer drive gearbox".

The Washer/spacer looks and fits like this:-

Hello Rudie,

Thanks for the info. I did look at various parts and workshop manuals and finally found the solution. The washer you mention is exactly what I needed but on all diagrams it is shown on the outside of the speedo unit whereas it should be on the inside between the unit and the right hand spindle support spacer. THis means the unit is pushed further away from the disc giving it a couple of mm clearance. I didn't see this mentioned in any manual I could find and it took a while to figure out but it made sense to do it esp as the correct washer fits exactly into a recess on the inside of the speedo unit.
I just love this bike, it certainly keeps me guessing and helps fend off dementia. Who needs to learn a foreign language or how to play a guitar when you have an old Triumph?
Many thanks to all who offered advice.
Magno

 

[Rocky]

Thanks for the update
I have run across incorrect diagrams in parts books too.
I mentioned that I had a similar problem too, and if memory serves correctly, I either had a missing washer or it was in the wrong place.
Reading this thread brings my memory back and I'm 100% sure I needed a correct washer/spacer too and the problem was solved.
I loved your language/guitar comment

 

[56Karmann]

my problem is the rear master cylinder is rubbing against the tire

 

[56Karmann]

and i only have a 76 parts cat. and and manual only shows rear drum no caliper

 

[Rudie]

The washer you mention is exactly what I needed but on all diagrams it is shown on the outside of the speedo unit whereas it should be on the inside between the unit and the right hand spindle support spacer.

Nope, completely wrong.

The workshop manual, parts manual and my photograph are absolutely correct. If your bike requires a washer in addition to the spacer between the speedo drive and the wheel bearing, your bike also has the wrong spacer - look at my photograph, note the gap between the wheel hub and the speedo drive.

My photograph shows how all Triumph twins with the underslung rear caliper were new. If your bike is not like that, your bike has incorrect parts. The usual error is to transpose right and left spacers (37-7003 and 37-7006). Or, your bike has two spacers the same, it has two short spacers.

Another possible - though less likely - error on your bike is the caliper carrier is bent.

I am surprised other '76-'78 twin owners did not pick up the error in your post earlier.

 

[Rudie]

my problem is the rear master cylinder is rubbing against the tire

I have posted a possible suggestion in your 1977 Bonneville resto thread. Please post the make and model of the tyre fitted on your bike.

i only have a 76 parts cat.
only shows rear drum no caliper

You do not. Meriden published two parts catalogues in in 1976 - in February and August. Both are online in several places - e.g. British Only Tech Library - neither shows a rear drum brake (last fitted to 1975 twins that were not exported new to the US).

manual only shows rear drum no caliper

If you mean a workshop "manual", the online version covers all '73-'78 twins and has several subsections in "SECTION F | BRAKES, WHEELS AND TYRES" dealing with both disc and drum rear brakes.

 

[Wavemaker]

I have posted a possible suggestion in your 1977 Bonneville resto thread. Please post the make and model of the tyre fitted on your bike.


You do not. Meriden published two parts catalogues in in 1976 - in February and August. Both are online in several places - e.g. British Only Tech Library - neither shows a rear drum brake (last fitted to 1975 twins that were not exported new to the US).


If you mean a workshop "manual", the online version covers all '73-'78 twins and has several subsections in "SECTION F | BRAKES, WHEELS AND TYRES" dealing with both disc and drum rear brakes.

F15 Rear Wheel. Page145/217.

 

[56Karmann]

first chance I've had to check my thread. thank you I did learn of the two catalogues. i also found that the air filters as well as hardware items were wrong. Air boxes won't fit carb to box connectors were also wrong. but now I'm having trouble with fuel and air/choke cable placement, I've checked several photos of 77 T140's with several different cable routes. just can't get throttle or choke to work smoothly.

 

[56Karmann]

Using a 78 parts catalog I removed spacers called for in April 77 catalogue and all's well with rear brake. still looking for rear brake hard line 60-7007 many distributers say they have iy but always out of stock.

 

[Wavemaker]

Hello Rudie,

Thanks for the info. I did look at various parts and workshop manuals and finally found the solution. The washer you mention is exactly what I needed but on all diagrams it is shown on the outside of the speedo unit whereas it should be on the inside between the unit and the right hand spindle support spacer. THis means the unit is pushed further away from the disc giving it a couple of mm clearance. I didn't see this mentioned in any manual I could find and it took a while to figure out but it made sense to do it esp as the correct washer fits exactly into a recess on the inside of the speedo unit.
I just love this bike, it certainly keeps me guessing and helps fend off dementia. Who needs to learn a foreign language or how to play a guitar when you have an old Triumph?
Many thanks to all who offered advice.
Magno

Totes agree regarding firewall on dementia.

 

[Wavemaker]

If you use the correct Triumph workshop manual for a T140V with a rear disc brake - 1976-1978 - it does, manual Section F14, page F21 is a full-page drawing of all the rear wheel components, the spacer is shown next to the speedo drive.


You would help yourself more if you used a parts manual as well (e.g. free to read online at British Only Tech Library?). Not only is the same drawing there, all parts are numbered and listed on a parts manual's following page; in this case, the spacer is "12 37-7021 Washer - speedometer drive gearbox".

The Washer/spacer looks and fits like this:-

Here is the page in my Clymer manual. Damned if I can spot the spacer. Please help me out.

 

[Rudie]

View attachment 49379
Here is the page in my Clymer manual. Damned if I can spot the spacer. Please help me out.

Meriden published two parts catalogues in in 1976 - in February and August. Both are online in several places - e.g. British Only Tech Library

The Clymer manual illustration is taken from the parts catalogue published in February 1976, that contains so many mistakes Meriden reissued it in August 1976; if you find the same drawing in the second edition, the spacer is beside the speedo drive.

 

[Wavemaker]

The Clymer manual illustration is taken from the parts catalogue published in February 1976, that contains so many mistakes Meriden reissued it in August 1976; if you find the same drawing in the second edition, the spacer is beside the speedo drive.

Gooday Rudie. Thanks for that. I'll have to up date, won't I? .

 

[bryanv]

Gooday Rudie. Thanks for that. I'll have to up date, won't I? .

I know this thread is a couple years old, but I'd like to add some observations I found on my stock 1976 t140.
Not all t140's use the tach drive spacer (37-7021) as shown in the parts diagram in the Aug catalog. In fact, there is an '*' next to the part number indicating that is only to be used with 'latest caliper plate 37-7020'. Earlier caliper plates have a 'spacer' pre welded onto them. If you look at various caliper plates off these bikes, you can clearly see that some of them have a spacer built in (mine does), and others do not.
If I tried inserting the 37-7020 spacer between the speedo drive and caliper bracket, there would be a visible gap between the spacer and bracket, unlike the photo posted in #5, which shows the spacer flush against the bracket.
In addition, back to the original issue posted by Magno, I too had the problem with the tachdrive gearbox rubbing aginst the hub/brake disc, and I also had to insert a washer/spacer to push the gearbox away from the hub 1-2mm.