TCS Detent Cam Questions

[HoraceM22]

Today's questions are regarding the 365 reverse detent cam.
I need to replace the "O" ring (Pt No. A0746178Z) behind the Reverse Cam - Pt No. B074F0225Z

After a quick look it seems that the gearbox support plate has to come off for a start.

1. Does anyone know what size the "O" ring is? Classic Team Lotus have never sold one!
2. How difficult is it to get the 1/16" pin out ? I assume that if it is on one piece it should come out with some grips. God knows what if it is broken - 1mm diamond drill anyone?
That's all for today - Off to see Nick Mason's garden - and cars hopefully!
Horace Marks

[jbcollier]

Changing that o-ring requires the rear cover to be removed.

[Dilkris]

Interestingly the roll pin which locates the reverse/5th gear external cam on your box appears to be also lock wired - probably because a PO thought its fitment to be looser than expected. Maybe you will be lucky and it will be easy to remove.
The real fun will start in removing the 5th gear rear cover   
Check for wear between the reverse/5th gear cam shaft and housing - if there is excessive play here you may well need more than just an oil seal change.
Keep us posted.   
   

[HoraceM22]

So, after a quick look, it seems to be (hopefully) and on a good day....

Find a correct "O" ring
Drain the oil.
Remove the gearbox support plate
Remove the roll pin and undo the locknut and remove the detent cam
Remove all the outer row of bolts  -   Is it necessary to remove any inner bolts, not sure what's located inside the cover?
Remove the end cover plate
Locate the old "O" ring, remove it and replace with the new one
Clean up the faces of the end of the 'box and and cover plate
Coat both these faces with sealant
Reverse the previous steps and refill with oil

Anything I have missed? apart from the time between some of these steps, Ho Ho Ho!
ATB
H.

[Kendo]

Is there an early step of selecting a particular gear before you remove the cover, so internal parts don’t fall out? Or is that for a different tranny repair?

[Footer]

I did this about a year ago and it was considerably harder than I imagined.  Very important to consult the shop manual before you start disassembly and Kendo is correct that a particular gear must be selected before you take the cover off, but I don't remember which one.  It is explained in the manual.

I was able to get the cover off without removing the transaxle from the car by loosening all the motor mounts and raising the body enough to get adequate clearance for removing the cover.  I had a post with pictures here somewhere but have not been able to find it.

Once you get to the o ring, I had trouble finding specifications and ended up going through a process of elimination until finding the one that fit the best.  That ended up being an "Oil-Resistant Buna-N O-Ring, 2 mm wide, 9.5 mm ID"  that I bought from McMaster-Carr here in the US.  I could not find one locally.  Their part number is 9262K671.  Unfortunately, they only came in packages of 100, but surprisingly only coast about 10 US dollars delivered.   If you send me the cost of postage, I will be happy to send you a couple out of my stockpile.  Send me a PM if you choose this route.

Getting the cover back on proved to be difficult as three small keys did not want to stay in place while the cover went back on.  My solution was to wrap them with a very thin rubber band to hold them in  place.  Once gears started moving the rubber band would be ground up into very small fragments that would not be harmful.  Someone else may have a better idea to accomplish this task and I would be eager to hear about it.

Should I find my post in the meantime I will post it.

Good luck!

[Footer]

Found it!
If you search for "365 Transaxle Leak" from June of 2024, you can see the process I went through.  Hope this helps.

[Dilkris]

I remember the post "365 Transaxle Leak"  well and have just re-read it.
"HoraceM22" please note the content of "jbcollier's" comment within this referred thread which he wrote on the 24th June 2024.
If you have an issue here, changing the O ring will have little to none, long term benefit.
Just out of interest "HoraceM22" first remove the spring and ball housing assembly which compliments the external 5th gear/reverse cam plate and with this removed how much lateral movement can you now feel between the shaft and housing? I think you'll be surprised - I know I was.         

[kram350kram]

Just info, but when assembling a trans and you need to hold pieces in place try Lubegard, Dr. Tranny Green Assembly Goo. Sticks everything to everything and just melts under operation. Great for holding individual needle bearing rollers, keys, pins, etc…

[jbcollier]

It can get complicated.  Europas are now officially old.  Things can be worn and require bushing.  These linkages and rear covers were frequently damaged by backing into things.  Not unusual to find the cover cracked and/or welded.  All that to say, who knows what you will find once you open it up.

[HoraceM22]

Ah. we always get a laugh from old JBC.
I just wish I had his knowledge and experience of these machines, but I'm getting there.

Re my leak (the car that is, so far) I enclose a pic of a day's worth of oil, but while I was down there I noticed the position of the spring loaded ball and thought that it may ought to be in the middle of the plate. I hope someone hasn't sawn of a piece of the shaft.
What do your balls look like, so to speak?
H.

[HoraceM22]

Regarding the size of the "O" ring, was the "overdrive" 5th gear made by Renault or for Lotus? Thereby might define whether it's English or metric.

[4129R]

The 1/2" diameter ball bearing needs to be completely central to the cam, or you will have trouble selecting gears, or the ball will fall out. 

[HoraceM22]

"Footer", Many thanks for your kind offer, but I'm sure I'll be able to find something that will do the job.

Re the ball, How can it be in a position not central to the plate?

[Footer]

Re:  Lubegard, Dr. Tranny Green Assembly Goo
Good piece of information I did not have before.  Thanks kram350kram