1962 Lotus Seven Differential Problem

[TEM]

Hello All,

 

I just purchased this car and having trouble moving it.  It has been sitting for some 30 years.  It will roll for a few feet and then suddenly feel like its in gear, like its pushing against the engine.  Pulling the car backwards seems to roll better and "resets" the diff so that it can roll forward for a few more feet before happening again.  I have disconnected the prop shaft at the diff and there is no change.  When watching from under the car I can see the diff trying to rotate downward when the condition occurs.  Could this condition occur if there is no oil in the diff?  Will check tomorrow.  Axle appears to be original.

 

Thanks,

Terry

[7Westfield]

Oil's not the answer

I'd be suspecting a broken gear tooth

[MV8]

Don't force it to rotate. If you must move it to a trailer to get it home, buy a floor jack and wheel dollies to move it into position. I expect it is rusted on portion of the ring gear not covered in oil for 30 years. It may be minor. Drop the center section and clean on the bench until the pinion rotates with little to no effort by hand.

[TEM]

Thanks for the replies.  It seems both suggestions require a removal.  The car is already in my storage garage so no need to move it again.  MV8, you say to drop the center section, what does that mean?  The axle appears to be a single piece with a bolted on nose section where the prop shaft attaches.  Do I need to take out the entire axle?

[MV8]

No need to pull the entire axle assembly if you have room to work. The axles should pull out the ends a few inches to clear the center section so it can be pulled from the front out of the housing. The complete center assembly (ring gear, differential, bearings, and pinion) should come out together once the axles are out of the way and the front bolts are removed. I expect the axles are retained at the hubs with press-on bearings and bolt on drum brake backing plates to keep the wheel/axle bearings from walking out of the housing. I have no experience with this axle.

Edited September 23, 2023 by MV8

[jbcollier]

Don't fly blind!  Get and read the S2/S3 manual in the downloads section!

[TEM]

With the rear of the car on axle stands, I can rotate one wheel and the other rotates smoothly so it looks like my issue is somewhere in the ring gear and pinion.

[TEM]

Thanks JBCollier, I didn't know the manual was there.

[ianashdown]

Is it not mandatory to share pictures?! 
 

Eagerly awaiting
 

Ian

[TEM]

Oh, sorry, I'm new here.  Not familiar with the customs.  Pictures Attached.  Still working to put all the pieces back on.

[IamScotticus]

check the whole axle casing for rust, replace outter shaft oil seals, check, refurb replace bearings,  pinon seal.  etc.

No short cuts.  

Axle should be from a Standard/Triumph 10 if the lug nut pattetn is 3.75".  

Try looking at Rimmer Bros. or maybe Moss for parts.  As well as any fan forums for resources and spares.

https://www.uniquecarsandparts.com.au/car_info_standard_ten

Almost everything that isn't body and sests on a seven comes from different English cars..knowing the cars and who has the parts is the key.

Edited September 24, 2023 by IamScotticus

[MV8]

Take pictures of the axles and center section after removal to determine the extent of the damage. If the axle had oil, the only rust may be on the ring gear (rusts easily). The other parts may have been in a new condition prior to storage and better than what is now available as a replacement part.

[jbcollier]

They are yanking your chain.  It's not mandatory to post pictures but sure appreciated.  You have a nice S2 project there, congratulations.  Unfortunately the diffs are a weak spot on the S2s.  Power kept going up but Lotus didn't up-rate the diff until they switched to the Ford diff for the S3.  I have an S3 and, while I appreciate the extra strength, the Ford diff is also physically longer.  That means wider rear mudguards.  The narrower rear of the S2 is much better looking.

 

All the best with your project!

[SENC]

There is a manual for the Standard 10 rear axle in the "downloads" section of the site.  Pulling the hubs/driveshafts is easier while the entire axle assembly is installed, but you definitely need a special puller tool as the hubs are easily bent (and not easily found).  It took several rounds of penetrant and heat and lots of patience with mine - one side in particular fought me for a couple days.  If you aren't familiar with the puller tool I'll find some pictures and where I got mine.  Also a good time to order and replace bearings and seals.  If you determine you need to fully open the box, I agree with MV8 that it can be done from below (with room), but I think I'd do it on the bench.  Removing/replacing the assembly isn't difficult and gives you the opportunity for a full cleanup and a coat of protective paint.  Mind the breather hole!

[TEM]

Thanks all,

This car was undergoing a complete restoration but the previous owner ran out of money and the car sat for many years in this partially restored state.  The axle looks like it was restored to some degree as there is no road grime on it and it appears to have been repainted.  But I have no records on what was actually done to the axle.  But if they did rebuild the axle they should have filled it with oil prior to reassembly in the car.  So, it Looks like I will need to pull this axle and go over it completely.  A good winter project!

 

Senc, I have a typical wheel puller but any information you can provide on your puller would be appreciated.

 

JBcollier, I have heard that ring gears and pinion are hard to find so depending on what I find, I may have to go with the upgraded axle (Escort? TR7?).  During the restoration, it looks like they went with the wider S3 rear fenders so, maybe blessing in disguise.

[TEM]

Looking at some pictures of Standard 10 axles on the internet, I see that most (all?) have a domed rear center section.  Mine is more flat like a cake pan (see picture in first post).  Could this mean I don't have a Standard 10 axle but rather something else?  Has it already been updated?  I will measure the bolt circle when I get a chance but wheels look original.

[MV8]

It looks like the cake pan was added; perhaps to increase oil capacity. Your drums and hubs will help identify if it is something else.

[TEM]

That maybe why they change the read fenders.  I'll be off line for the next few hours but will report back later this afternoon.

[SENC]

I didn't look closely enough at your photo to notice the flat cake pan on its rear.  As MV8 said, could have been a mod for oil, or perhaps a way of strengthening.  There should be some markings on the nose/front side - maybe grab pictures of those and any other distinguishing features and someone may help definitively identify.  The Standard 10 axle has a breather hole on top of the right side casing arm.  I'll find and post a picture of the hub pulling tool.

[SENC]

Here is a picture of the churchill-style hub puller from a post I made on another site.  As I suspect is obvious, it bolts to the hub and supports it at the entire circumference, reducing the risk of bending the hub with other types of pullers.  The central bolt is tightened against the half shaft.  Generally, a couple cycles of penetrant and heat before mounting the  a good crack in the tightened bolt with a small sledge will break the taper seal and allow the bolt to be turned further extracting the hub.  As noted in my post, I really had to wail on one side and ended up slightly distorting the thread end - but that was fairly simply machined.

 

Once the hub is out, the half shaft should come out without much effort - but (on the opposite side of the difficult hub), the half shaft was quite stubborn and I had to rig up a set of spacers and use the wheel nut to pull it.

 

 

Once you confirm you have a S10 axle, the following semi-active forum may be useful to you in any rebuild.