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Rear diff and brake drums - OMG

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Due to seized brake cylinders on the Eclat it has been necessary to do the job I never wanted to do, remove the diff/inboard drum assembly. Jesus wept.

If there was ever any job on a Lotus that made me question not only Colin Chapman's parentage, but my whole commitment to the marque this was it. What an arsehole, idiotic, pointless setup. Had to laugh at the thought of that famous picture of the development team collecting the Don Safety Trophy for the Elite, and wondering if somewhere around the same time there was a band of Lotus dealer mechanics with a golden raspberry award they never had time to hand out. Colin Spooner should be knighted for throwing the whole bag of shit away and creating the Excel.

No wonder people carve holes in the body to adjust the handbrake, even with the help of people with far greater mechanical intellect than I will ever have (Thanks Steve semi_42) it's took a solid 8 hours of sawing through seized studs, rusty rods, inaccessable clevis pins, and disassembling everything in a 1m radius just to get the damn thing on the floor.

Anyhow after a little well deserved rant; is there anything that can be done to improve matters when reinstalling to help out if God forbid there is a NEXT time?

1. The handbrake cable looks fine and I didn't need to spend another £40, but should I fit a new one just in case?

2. I'm making a new handbrake link rod out of stainless with stainless yokes and pins, but that doesn't make them easier to access. Should I be at least drilling some little pilot holes for bodywork access plates?

3. Is there any way of testing the diff whilst off? This was bought as a ground up restoration and I'm conscious the car has done 0.0 road miles with me. If I get it on the road and the first thing to be heard is a whining diff I'll hang myself.

4. Any other wisdom from owners who have "been there"?

PS I've been looking at the rusty rear seat lap belt mounts for a bit and planning to replace them, until during this exercise noticed one of the 2 mounting bolts is bang up against the chassis. I know Lotusbits sell new stainless ones, but how on earth do they fit?


In the garage no-one can hear you scream 

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Sounds like you have been having fun....

The rear seatbelt mounts arent bolted from the outside. The nut you are seeing is a captive nut thats welded to the mount and recieves a bolt from the seatbelt that goes through the glassfibre body and into the captive nut. You crank it from the inside of the car after removing the rear seat pad (or if like me you find it instantly shears at the merest sight of a power bar, you cut through the captive nut and bolt with a 4 inch grinder and they just drop off (I then sliced mine in two to remove more easily). Fitting is a bit of a fiddle, but they do go in under the triling arm with a bit of wiggling. I do recall having to slim one down slightly with the grinder for an easier fit - strangely the other one fitted without drama. A worthwhile tip is to stick the new mount to the fibreglass body with silicone sealant as it helps hold it in place when you are lining it up for the bolt. Without the silicone its a pain if your working alone.

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Hi Mark

Been there,done it,several times,its a nasty job removing the diff and its a very heavy lump,i guess you did it but remove the drums first as it helps with space and if i remember rightly it comes out at an angle not directly square,the handbrake setup is terrible and very tricky to undo,mine has loads of grease/oil on it all but if its not been out for years then its a nightmare.

One word of advise unless you have already done it is to get the prop rebuild or at least checked and balanced as you have the ideal opportunity whilist the diff is out.

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  • 4 weeks later...

I am waiting delivery of a 'new' diff from Lotusbits for my Eclat as the old one whined and leaked, I have dropped it partly out to do the front oilseal but I must do the change this winter due to the horrible whine.

I have been advised that this is the time to replace the rear brake bits, the side seals on the diff, waxoil the newly exposed ironwear and possibly the brake pipes.

I too am dreading the job and as it will be done on the garage floor rather than on a ramp, and I know that the weightlifting aspect is pretty horrific but I would welcome any constructive advice!

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Good luck Peter. I didn't take many pics but was thinking of doing a guide article. A friend is also fabricating a new bracket for me, and I've cobbled together a system of threaded rods and clevis for the handbrake, both to make the whole shebang easier to reassemble and drop again. Borrowed a Dremel to cut an access hatch in the floor too.

The worst bit was trying to wangling it out, as someone observed it had been assembled on the chassis THEN the body dropped on. Thus the diff was hanging on 2 brake pipe bends with me underneath looking up and wiggling it. One wrong move and you will never make the cover of Vogue again.

If you get stuck PM me

In the garage no-one can hear you scream 

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Hi all

Just about to put the diff back into the Eclat and......nagging doubts about not doing a couple of "just in case jobs" are filling my head.

I have had good news about a possible gap in the paint sprayer's schedule so need to get my arse in gear and sort it. I don't want to do any of this diff/brake stuff again, but then again don't want to turn this into a fanatical restoration I don't have time/money for.

I bought this Eclat as a non-runner so have no road miles on it personally and don't know what if any issues it had. I also don't know how long I will keep it; it feels like a top drawer car, eager engine, everything tight etc, but my Elite Riviera (waiting forlornly in the wings) was supposed to be the "real" project, the Eclat was just a great car I didn't want to see get broken for spares, which was a real danger at the time.

Just fishing for everyones experiences on;

1. Replacing diff seals on input and output. Never done these, presume not expensive parts but can I disturb anything critical internally by my amateur fumblings? Is it best done by a proper mechanic as part of a refurb?

2. Driveshaft refurb - seems a good idea, but car is arse up and nose tight against the garage wall, not great access at the front. Is it bolted at the engine end or free-floating splined? If I withdraw the shaft to the rear and remove it, how hard is it to feed back through the chassis with the nose of the shaft presumably wanting to droop? Is it tricky to feed into the gearbox?


In the garage no-one can hear you scream 

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I have heard about the brake pipe saga and am hoping for the beast there, If all goes t*ts up and I have to chop a hole in the floor, where do you do it?

I am going to make a cradle for the dif and put that onto a trolley jack to do the lif in/out bit but I am still dreading the whole thong

Thanks for offer of help


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Trolley jack is definitely the way to go when dropping the diff, that how I dropped mine and its fairly simple if you keep it balanced and take it slowly. I've cut holes under the seats in mine to be able to reconnect and simply adjust the handbrake, this greatly simplifies the task and I'd certainly recommend this mod as it will also make removal in future much less hassle.


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Ok so you take out the rear seat and dig a hole in the middle somewhere?

The oilseals need to be done but I remember hearing something about having to take the conical ring off, I will look at the book before I start

I will do a proper report for the forum when done, it is interesting that Lotusbits quote 10 hours for diff swap with replaced oilseals and brake cylinders and they have the ramp and experience.

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I would wait until it's out to drill and mark where to cut the holes in the underside of floorpan. The actual useful gap is smaller than you think and triangular, so you don't want to be making a hole bigger than needed. Plus it's more of a help on reassembly than removal IMHO (the stuff you will cut to drop the diff is probably toast anyway; clevis rod, brake lines etc.)

In the garage no-one can hear you scream 

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  • 1 month later...

I have now got the replacement diff and is new seals but the book shows that I need to chisel off the rings on the output shafts and replace them with new ones. I wish to make my own to save buying them in, the problem is what size do I make the bore to allow for the shrink fit needed to keep all the bits in place. Can any one help?


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  • 9 months later...

It feels like a lifetime ago now, or did it just age me a lifetime? Definitely more grey hair since then.


I thought the diff was the end of nightmare jobs, then a few months back came.....the brake servo :help: 


God forbid the heater or wiper motor packs in.

In the garage no-one can hear you scream 

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OK I have got the diff out and replaced, I asked all my contacts for advice and now ant to pass on the knowledge for those poor souls who have got to do it themselves.

Firstly it is a long job, Lotusbits allow 10 hours with 2 people at it for some of that tine so be prepared for a long and hard haul.

so this is what I did.

1 jack the car up as high as possible and make a cradle to hold the diff, this is a tee piece with the top of the tee the distance between the brake backplates,I made mine out of 3" x 1 1/2" tube, then make a pair of vertical pieces with cutouts to fit round the webs on the underside of the diff by the output bearings these are just tall enough to enable the top of the T to miss the bottom of  the diff. now weld the vertical member of the tee to reach forward in line with the prop shaft and cut it off just short of the slot in the dif frame so you can reach the prop shaft nuts.

2 position this cradle under the diff and measure from the top of the diff to the bottom of the cradle, this is the minimum lift you will have to raise the back of the cat by, To this add the height of the trolley jack (if that is the way uou are going ) and raise the car accordingly

3 if you can get a ramp and an engine hoist there is a better way, take the arm off the top of the hoist and fit a plate to the top of the ram to support the cradle.

4 using the ramp method, you can now put the car on the ramp and raise it right up, put the hoist beneath the dif and lower the car until the cradle is just holding the dif and starting to take the weight of the car.

5 undo the road wheels

6 put  wooden blocks under the jacking points 

7 lower car onto the blocks and remove the cradle

8 remove drive shafts and brake drums

9 slacken the horizontal and vertical bolts holding the diff cage into the car

10 temove prop shaft bolts

11 remove the horizontal studs holding the dif into the car

12 remove the handbrake r clips, a pointed rod will help push them out

13 remove handbrake clevis pins

14 put the cradle back into position and take weight of the dif

15 remove the vertical diff studs

16 disconnect the rigid brake pipe from the diff

17 push the diff to one side and gently lower it about 1" rolling it at the same time so the brake fitting on one of the  the drum backplates passes below the chasais member

18 repeat for other side,

19 lower dif and pull engine hoist clear.

Replacement is the reverse, but be careful threading the brake fittings back into position.

You can do it with just a trolley jack if you must, but it is horrible.

One other tip, when you replace the dif output shaft bearings and seals, you will find that there are two o rings to be replaced, the manual says to glue thim in but if you also bolt the drum back plate to the housing with m5 nuts and bolts with the nuts to the inside, it is possible to just engage the housing with the diff and then remove the nuts and bolts before pushing the bearing housing home, this will stop the o ring from falling out of position.

Good luck

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  • 3 months later...

The answer on when to replace the joints is : when you hear them click or if you get a lot of slackness with the car being inspected with the wheel of the ground. It is not something that you can say replace every X thousand miles.

Some joints last longer than others.

I need to rebuild a couple of spare shafts, so will take some pics and post a how to guide, but it won't be for a month or so.

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As I recall, the u joint for the propeller shaft is the same one as on the rear half shafts.


I would only replace them if there was a noise to indicate they are bad or if they have movement when checked manually.


I found some resources (listed below).


It is easy to do he rear half shaft u joints with the car on jack stands, but for the drive shaft u joints, the engine or the rear differential has to move so it is a big project.


This is a VERY common u joint in the US and was / is used on all sorts of vehicles and machines.


I wouldn't pay a lot for one, maybe $15USD a piece for good ones.  I would only use Dana/Spicer or Moog brand in that order for the propeller shaft as it is such a big job to replace.


take pictures.







this is the best page



has the following u joints listed.


A075D6004 TRW 20021; Hardy Spicer 94/548450; GKN HS163; Dana Spicer 5-153X





has the following u joints listed (and the dimensions of the part)


Neapco 1-0121
Dana/Spicer 5-200X
Neapco 1-0153 -- In Stock, Our Price: $ 12.41
Dana/Spicer 5-121X
Rockwell/Meritor CP121X
Borg Warner 114-520
Rockwell/Meritor CP153X
Borg Warner 114-3HD
Borg Warner 114-513
Chrysler 1818920
Chrysler 1818921
Chrysler 4882793
Chrysler 5015694AA
Chrysler 5161766AA
Ford 6L2Z4635A
Ford 01Y7039
Ford 21C7039
Ford 211C1118397
Ford A9LY4635A

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I fitted the Dana Spicer5-1310X which are supposed to be even stronger than the 5-153X( and about USD4 extra I seem to recall), but they are not greasable, whereas the 5-153X are. They fitted perfectly, and they supply different thickness circlips too. Have no road use yet to test longevity, but if 'greased for life' is true and the life is long then I like that idea. One less maintenance item works for me!  I think they were around the USD17 mark. Postage for 6 pieces was about USD50 to Oz.


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