Lotus Europa Community
Lotus Europa Forums => Garage => Topic started by: HoraceM22 on Friday,June 06, 2025, 01:51:25 AM
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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
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Changing that o-ring requires the rear cover to be removed.
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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 :FUNNY:
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.
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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.
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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?
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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!
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Found it!
If you search for "365 Transaxle Leak" from June of 2024, you can see the process I went through. Hope this helps.
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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.
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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…
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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.
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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.
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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.
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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.
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"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?
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Re: Lubegard, Dr. Tranny Green Assembly Goo
Good piece of information I did not have before. Thanks kram350kram
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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.
I have the Haynes manual for the Renault 15 & 17 and the 5th gear "arrangement" is shown and described as the "early type 365 rear cover and rocking lever", which suggests the "O" ring in question will be metric.
I believe, although I am prepared to be corrected, that for the Europa TCS, the 5th gear itself was made by Hewland, (a British Company), to a design specified by Lotus.
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"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?
The aluminium block in which the ball moves may not be positioned correctly. That happened to me.
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The Renault 365 transaxle came with 0.93 fifth gear and a 3.7x final drive. The 336 transaxle had a 3.5x final drive. A straight switch to the Renault 365 would have meant that the five speed Europa Special would have been slower than the four speed version. So, Lotus had Hewland make up a special 0.85 fifth gear. At the same time, also removed the fifth gear detent and came up with their external detent system. Perhaps they were concerned the extra mass of the Europa shifting system would make the stock detent ineffective. Regardless, the weird double-pivot, linkage was Renault, not Lotus. Rear covers are the same.
I do not like the 365 shift mech: too exposed and more wear/leak points. When I finally get around to my 395/352/365 franken transaxle, it will have a 395 rear cover and shift mech.
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Regardless, the weird double-pivot, linkage was Renault, not Lotus.
What do you mean by the double-pivot linkage?
Do you mean the rods going from the gear lever, with the UJ by the exhaust manifold, and then attaching to the gear selector rods with a roll pin, or do you mean the spring loaded 1/2" ballbearing onto the indented plate/cam which prevents over rotation when selecting reverse and 5th gears?
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So to jump on your thread. I fitted a new o ring to the double pivot selector assembly that the lotus dedent mech attaches to, it made no difference to the amount of oil coming out... so it must be worn... there is a fair amount of play in it.
Have you guys rebushed this area and stayed with the o ring, or fitted a seal similar to the sector shaft below it.... I hope that makes sense.....
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So to jump on your thread. I fitted a new o ring to the double pivot selector assembly that the lotus dedent mech attaches to, it made no difference to the amount of oil coming out... so it must be worn... there is a fair amount of play in it.
Have you guys rebushed this area and stayed with the o ring, or fitted a seal similar to the sector shaft below it.... I hope that makes sense.....
You comment makes perfect sense.
I too have an oil leak from this area and looking and feeling the lateral play, (which can clearly be seen once the spring loaded ball arrangement is removed from the cam plate) I just know that changing the "O" ring will not solve the problem and that sleeving the housing will be required.
(Note: I sleeved the housing plus new oil seal for the gear change at the time of rebuild and "assumed that the "O" ring in this shaft would be ok......it isn't :confused:)
I have yet to remove the 365 rear casing to see if the casting has sufficient material to be machined in order to support the fitment of an oil seal - sure sleeving will be possible, but an oil seal (which would be ideal) I don't as yet know.
I'll post when I do.
Unless somebody already knows.
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Thanks Dilkris.
I have fitted a new gear selector shaft ( which was worn) and seal, it's worked perfectly.
I have removed lotus dedent mech, spring and ball and the bit with the ears. Fitted the renault 5th gear internal spring and plunger, and a sleeve and guide on the gear lever in the cabin. 1st n 2nd have never been so precise or easy to change gear.
I am going to remove rear cover hopefully this weekend, and get a local machinist to give me his appraisal, keep you posted.
I too use a heavy grease to keep things located upon reassembly.
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I thought the cam only moved when the gear stick was moved side to side, and only depressed the ball bearing at the extremes, i.e. reverse and 5th.
The change 1st to 2nd, should not involve any movement of that cam.