Restoration Impossible: Rebuilding the Rear End

Sep 27, 2017 update to the Lotus Elan project car

The bespoke Lotus housing, combined with stub axles, is mated to a standard Ford differential to make the Elan have independent rear suspension.
The stub axles, new bearings and gasket came from R.D. Enterprises. Now the entire unit is ready to put together.
And now our differential is ready to be installed, Bushings hold the top of the differential to the frame and torque rods with rubber bushings allow the bottom of the differential sight movement under acceleration.

Before undertaking the rear suspension rebuild and assembly, we wanted to get the differential rebuilt and in place. This is critical because the suspension’s Roto-flex couplings and half shafts mount to this differential.

Based on a common English Ford unit, the front half of the differential is nothing fancy. What makes this differential special is not the ring and pinion gears and bearings, but the bespoke Lotus cast rear housing and differential mounting bushings used on the Elan.

The early Elan was offered with a 3.9:1 final drive. In an effort to improve the car at highway speeds, the later cars were offered with 3.7:1 final drive gears. Since we had a late parts car and had already updated our engine to the later car’s slightly higher horsepower figure, we felt safe in using the later and lower (numerically) final drive, which would make our car run lower rpm at higher speed.

Of course, in a rather long list of things that would have been good to know before we started on this project, the flange that connects to the driveshaft on the later differential has a different, wider bolt pattern than that of the early differentials.

Thankfully, we were able to get the driveshaft back out of our still bare chassis, and make the correction. We just had to use the flange off of a later driveshaft we had in our parts stash.

As for the rebuild, the Ford gears are robust and were in good shape, so we cleaned, painted, added new lubricant, and installed new bearings and gaskets into the differential housing.


Join Free
Join our community to easily find more Lotus project updates.

Reader comments:

wschaub
Sept. 29, 2017 7:52 a.m.

Did you install the stiffening bracket that spans the upper mounting ears on the aluminum casting?  Lotus added these to later Elans.  If not, it may be worth considering.  I'm following this restoration with great interest as I am restoring a 1972 Elan that has been sitting since 1987.

Tim Suddard
Tim Suddard Publisher
Oct. 12, 2017 6:20 a.m.

In reply to wschaub:

I did not add those stiffening bracket. We are trying to restore this as close to original as possible. I did stiffen the engine mounts, as they were torn.

wschaub
wschaub New Reader
Oct. 12, 2017 3:03 p.m.

You may want to talk to Ray @ R.D.  That differential bracket was a running change Lotus made, I think with the Sprint.  It is a pain, even with the body off.

Tim Suddard
Tim Suddard Publisher
Oct. 15, 2017 7:43 a.m.

In reply to wschaub:

I have been talking to Ray at least once a week, about every step in the restoration. He has been a great resource and a great guy.

You'll need to log in to post.

All 1964 Lotus Elan updates

1 week ago

Restoration Impossible: An Alternator That Looks Like a Generator

1 week ago

Lotus Elans are legendary for electric gremlins.

2 weeks ago

Restoration Impossible: Finishing Off the Engine

2 weeks ago

We add the air box and air cleaner.

2 months ago

Restoration Impossible: Running New Lines

2 months ago

The final steps in finishing off our chassis were to replace the brake and fuel lines.

2 months ago

Restoration Impossible: Rebuilding the Rear Suspension

2 months ago

The rear suspension on a Lotus Elan is much more complicated than the front suspension.

2 months ago

Restoration Impossible: Rebuilding the Rear End

2 months ago

Before undertaking the rear suspension rebuild and assembly, we wanted to get the differential rebuilt.

3 months ago

Restoration Impossible: Rebuilding the Front Suspension

3 months ago

Our Lotus Elan's front suspension comes together.

4 months ago

Restoration Impossible: Rebuilding the Brake Calipers

4 months ago

We rescue our Lotus Elan project's fused-together brake calipers.

4 months ago

Restoration Impossible: New Gelcoat for the Body

4 months ago

Our project 1964 Lotus Elan gets body repairs and new gelcoat.

4 months ago

Restoration Impossible: Painting the Frame

4 months ago

Our 1964 Lotus Elan gets its frame painted with Eastwood

5 months ago

Restoration Impossible: Strengthening the Frame

5 months ago

After strengthening our project Elan's frame, we wanted to strengthen it.

5 months ago

Restoration Impossible: Removing the Rear Hubs

5 months ago

Our friends at Sevens & Elans help us remove hubs that had been wasting away for 40 years.

5 months ago

Restoration Impossible: Ordering the Final Parts

5 months ago

We order the last of the needed parts to complete our Lotus Elan restoration.

6 months ago

How To Straighten a lotus Elan Frame

6 months ago

We grafted three frames together to make a perfect one.

6 months ago

Restoration Impossible: Shining the Chrome

6 months ago

Our project Lotus Elan needs some chrome refreshed.

6 months ago

Restoration Impossible: Gauges Like New

6 months ago

Nisonger brings our Elan's destroyed gauges back to life.

7 months ago

Restoration Impossible: Dismantling the Chassis

7 months ago

It's time to dismantle the chassis of our project Lotus Elan.

8 months ago

Restoration Impossible: Fiberglassing the Bottom

8 months ago

We thought we made good progress. Then we flipped the car over.

9 months ago

Restoration Impossible: Starting Fiberglass Work

9 months ago

Learn how to make fiberglass repairs.

9 months ago

Restoration Impossible: Working on the Wire Framework

9 months ago

Our project Lotus Elan needs some structure repair around the doors.

9 months ago

Restoration Impossible: Making a Trunk Mold

9 months ago

Our Lotus Elan's trunk has a 6-inch hole. Here's how to create the replacement piece.

9 months ago

Restoration Impossible: Grafting in a Whole Quarter of the Body

9 months ago

The left rear quarter of our Elan had been hit hard. Here's how you seamlessly graft in a replacement piece.

10 months ago

Restoration Impossible: Getting the Door Hinges to Work

10 months ago

Our project Lotus Elan is still in the beginning stages of a restoration.

10 months ago

Restoration Impossible: Preparing to Cut the Body

10 months ago

Once you cut, you can't go back.

10 months ago

Restoration Impossible: Starting to Rebuild the Missing Back End

10 months ago

We decided to start our Lotus Elan's restoration with the toughest part first.

11 months ago

Restoration Impossible: Starting Work on the Body

11 months ago

We are getting back into our Lotus in earnest.

1 year ago

Our Elan Gets a Decklid

1 year ago

After lots of searching we find a rare Elan decklid suspiciously close to where we bought our project.

1 year ago

Our Elan Gets Blasted

1 year ago

After a trip to Blast Masters, we see if the fiberglass is salvageable.

1 year ago

One Fresh Elan Engine

1 year ago

With another trip to Twin Cam Sportscars, our Elan's engine is completely refreshed.

1 year ago

A Look Inside Our Lotus Elan's Transmission

1 year ago

We refresh our project Elan's gearbox with the help of Twin Cam Sportscars.

1 year ago

Incredible tranformation: Lotus Elan Carburetors

1 year ago

Our Lotus Elan's carburetors get taken from trash to treasure.

1 year ago

Lotus Elan Frame Dilema: Solved

1 year ago

Our Lotus Elan's frame was bent and broken. How did we solve the issue?

1 year ago

Soda Blasting Our Lotus Elan

1 year ago

Our Lotus Elan takes a trip to Blast Masters to get stripped.

1 year ago

Our Lotus Elan Gets Stripped to the Bone

1 year ago

With our Lotus Elan's engine refresh underway, it was time to start disassembly of the rest of the car.

1 year ago

Restoration Impossible: A Look Inside the Elan's Engine

1 year ago

With the help of Twin Cam Sportscars, we tear our Elan's engine apart.

1 year ago

Lotus Parts Pour In

1 year ago

We find lots of parts for our project Elan thanks to our friends.

1 year ago

Finding a Windshield

1 year ago

Our Lotus Elan gets some fresh glass.

1 year ago

The Parts Search Begins

1 year ago

Our Lotus Elan needs a lot of work and parts. Here's the initial list of what we need.

1 year ago

Figuring Out What We Really Have

1 year ago

After lots of cleaning, we organize our project and assess the situation.

1 year ago

Our Lotus Makes it Home

1 year ago

After dragging our new project to Florida, we begin cleaning it out.

2 years ago

Our Lotus Elan's First Concours Award

2 years ago

Still in pieces, our impossible restoration project attends its first show.

2 years ago

How Not to Load a Lotus

2 years ago

We had to get three-quarters of a lotus from Michigan to Florida.

2 years ago

Restoration: Impossible

2 years ago

Meet our new restoration project: a very rough 1964 Lotus Elan.

BUY THE BACK ISSUES!

The Latest

My Racing Rules

3 days ago in Articles

Like most of us, Classic Motorsports Publisher Tim Suddard is obsessed with cars and racing.

Classic Motorsports Car Catcher: Peter Brock's Ultimate Datsun 510

5 days ago in News

Classic looks and 300 horsepower built by a legend.

Show Us Your Shop Contest: One Week Left

6 days ago in News

3-car? 1-car? parking lot? We want to see where you mess with your car. Our favorites win some major prizes.

Forgotten Fiberglass

1 week ago in Articles

In the ’50s and ’60s, the resin revolution turned dreamers into car manufacturers.

Restoration Impossible: An Alternator That Looks Like a Generator

1 week ago in Project Cars

Lotus Elans are legendary for electric gremlins.

Tech Tips: Jaguar E-Type

1 week ago in Articles

A sophisticated, achingly beautiful two-seater with Ferrari-like performance at an affordable price.

Our Preferred Partners

Mlassic Motorsports Magazine

Subscribe Today

Also get your instant access to the digital edition of Classic Motorsports Magazine!

Learn More
xb5vM4qG4tSm1uB7aanM9aJ4Ta4ZttRM