Diff Installation

[richard sprint]

I had my diff restored by A1 Gearbox at St Neots. Today I tried to install it what a bugger to try and get it into position, the manual states coming in from the nearside but there was no way this was going in with the metal strengthening plate fitted to the diff.

So removed this and tried again - even then it was a job and three quarters! In the end it was a matter of brawn over brain and finally with much paint scratching it was in but then of course had to fit the strengthening plate.

The single long bolt that secures the strengthening plate to the diff could not be accessed as insufficient room to slide it into the bush. In the end I had to drill a hole in the chassis to allow me to pass the bolt through and then I managed to screw it home and tighten with a ratchet spanner.

I don't think I missed a trick I just think the tolerance to accept the diff is too tight? Why I wonder didn't Lotus allow more space in this area.....

I've now got to repaint the scratched areas.

Anyone else experienced this problem?

Richard

[Chrisrich]

Yes, I did. Exact same thing.
While I was pulling the diff to put in a set of CVs, I was advised to add the stiffening brace. Frankly, I was reluctant, as I remember how hard it was to get the diff OUT, I couldn't imagine what would happened if I added 1/8" on each end of thickness. Sure enough, after about 2 hours of fighting with it, I gave up and took the brace off. I got the brace-less diff in in about 15 minutes. When I saw the reality of putting the brace on AFTERWARD, I just gave up and sent it back.

You're a better man than I.


Chris

[Frank Howard]

Richard,

Part of the problem is the rear end of the chassis being bent upward from years of jacking the car up at that point. I took a sledge hammer to mine, knocking it back down to give a little more clearance.

[richard sprint]

Frank

I should have mentioned that mine is an unused replacement Lotus Chassis - cannot say new as its 20 years old - but certainly not bent by jacking.

I cannot believe Lotus would have made it so difficult if for no other reason than wasted time when a new assembly....

Chris

At least it was not just me! I thought the drilled hole would keep to Chapmans policy of adding lightness....


Richard

[rgh0]

By design the diff is a light press fit into the chassis. It gets easier the second or third time as you learn the subtle angles and turns to get it in. I got the diff brace bolt in without drilling a hole in the chassis but I cant remember how.

A spyder chassis is a much easier fit.

cheers
Rohan

[garyeanderson]

By design the diff is a light press fit into the chassis. It gets easier the second or third time as you learn the subtle angles and turns to get it in. I got the diff brace bolt in without drilling a hole in the chassis but I cant remember how.

A spyder chassis is a much easier fit.

cheers
Rohan

I look at it as a learning tool, Some of the words that came out of my mouth concerning Lotus design had never been uttered before, possibly since. Anyway the diff brace goes on after the diff is installed in the chassis, and 2 of the 6 large diameter washers are omitted (if its a new install). Once the diff was in place (as Rohan says you learn a little each time you install or remove it) the bracket is placed into position and the single 5/16" bolt is hand tightened till snugged up. I think I used a racheting box wrench to do the final tighting. Then the top differential mounts (frustacones, a nice word isn't it) are dropped into the chassis (this gives a bit more room to struggle around in) and tighteded, finally the bolts through the lugs are installed as per the drawing (page R4 figure 3) in the Elan Workshop manual.This was on a galvanized Lotus chassis, haven't fitted one to the Spyder chassis.

Gary

[stugilmour]

Removing the diff from my old stock chassis was so difficult I ended up cutting it out. Old chassis is heading to the bin anyway. Hadn't thought of the chassis damage from jacking, but this probably contributed in my case.

Putting diff into the Spyder frame was really easy (Plus 2, but assume basic clearances are similar in Elan). Slipped right in with the extra clearance provided. Was able to install an eBay sourced diff brace later without undoing the driveshafts. Spyder has provided a beveled cutout where the lengthened 5/16" bolt goes through the diff brace into the diff. Provides enough room to finesse the bolt into place and hand start it on the diff threads. Still a bit tight to get the wrench in to tighten. Mind you, this is all with the body off so access was easy from the top; would still probably be difficult with body in place.

Question: As my driveshafts were in place, I installed the "frustacone" through bolts from the top, with the nut below the diff ears. This is opposite to the reference drawings (Figure 3 in the R section of the Plus 2 book, but assuming same for Elan). Is this OK, or will it end up impossible to remove the through bolts once the body is positioned? This is the only issue I can see with the different orientation. Through bolt cannot be inserted from bottom with my CV solid shafts in place, but easy fit from top.

[garyeanderson]

Stu

Are you going to pull the fuel tank and rear window when the newly sourced frustacones fail on your Plus 2?

Gary

[stugilmour]

Gary, thanks for the quick response.

My Fustacones are brand new and mounted in the Plus 2 Spyder chassis. Spyder chassis instructions suggest enlarging the body cut-out in this area because the Fustacone is oriented parallel with the space frame member rather than angled as in the stock set-up. Fustacones are attached by a couple of bolts from the top, threaded into nuts welded to the bottom of the space frame member, so they should be easily removable from the top side. In the Plus 2 the gas tank sits on top of the Fustacone "shelf" behind a vanity panel in the trunk. It is spaced out by straps with rubber strips to sit proud of the bolt heads, and the Lotus book calls up foam spacers in this area as well; PO used weather stripping on my car and will probably do something similar. Gas tank can be easily removed through the trunk with the rear glass in place. Due to the retaining bolts for the Fustacones being from the top, tank would have to come out to replace them.

Without the benefit of the body (it's about 60 miles away at the body shop), I am unsure of exact spacings in this area when the body is installed. Appears to me there should be enough spacing as the tank height is well over the 4" length of the through bolts. The tank height is approximately same as the towers. If this is the case, I think it is preferable to mount the 4 inch long through bolts to the diff from the top side, but trying to make sure as it looks like such an obvious improvement I am worried I am missing something?

There is a rather poor picture of my rear suspension set-up set-up in this thread. Just figuring out how to post a pic correctly as having difficulty getting correct format & size, so if further photo's required I can post later.

elan-plus-f13/never-use-your-rotoflexes-t18362.html

You can hopefully see the inner CV joint will interfere with insertion or removal of the through bolt if it is inserted from the bottom up. Not sure if this is the case if the Rotoflex was in this inner position or not, and also not sure of the Elan spacings in this area? Do I have it wrong, and it is possible/advisable to change bolt orientation as shown in Workshop manual?

I do not have an Elan available to compare the two cars, nor do I have the Elan Workshop manual, just the green Brooklands book that covers both cars. I do have the books for the Plus 2. If, as your post suggests, there is less clearance in this area on the Elan, I am thinking it might be a case of they kept the through bolt configurations the same in the Plus 2 even though there is room to do it a "better" way?

As usual, any help appreciated. Sorry to hijack the thread a bit.

[garyeanderson]

Stu

I don't know much about plus2's, I sold mine so I didn't do the work. There are folks here that may be able to tell you more about what you are up against here. I seem to remember reading that its a royal pain to replace the frustacones. The search engine sucks on this forum (it doesn't like common words like petrol or fuel or tank) so I used google

http://www.google.com/search?hl=en&sour ... f&oq=&aqi=

and I found this photo of Bob's install in his plus2
elan-plus-f13/replacing-fuel-tank-t17910.html

To me its a lot easier to loosen and move the tank enough to allow access to get at a 9/16" nut and the 3/4 inch long bolts that hold the frustacone than it is to remove the tank conmpletely to pull up a 4 inch long bolt. Its you car so do what you think is right. I won't be doing the work. All my Elan's have the bolt installed from the bottom with the nut on top and I don't have a tank sitting on top and have not had problems with the bolt "dropping out" but someone else has.
elan-photos-f18/progress-report-roller-t17665.html

Gary

[stugilmour]

Thanks Gary. Very helpful, particularly the pics and the Google tip.

As I don't have the body here I cannot be sure, but think I will go with current configuration. I am not sure one could lift the fuel tank enough to get the frustacone and it's associated retaining bolts out anyway. The cone itself would require about 3" to 6" upward displacement of the fuel tank I reckon. Besides, don't really fancy removing the drive shafts to put the through bolt in from the bottom!

Cheers & thanks again.

[garyeanderson]

Hi Stu

I think if you can lift the tank 2 inches you will be able to get the frustacones out. Even if it were 1 3/4 " it could be done. With the bolt head on top it is a tank out.

p.s. - Beauregard doesn't listen to me either...

[bluesbrother30]

Gary Anderson, will you contact me off line..........

Mike Summers
[email protected]