SVO Rear End Restoration

[bluemax]

After the MCA Savannah National last Fall, it was time to begin working on the under carriage of my '86 SVO Comp Prep. The car was sold originally in the Chicago area and was the daily driver of the first owner until 1996. So, while the car is under coated, the bare metal components took a beating.

In the first pictures you see the complete rear end and various close up shots I took for documentation. While this is an original 7.5 rear for the SVO, the restoration process would be similar for other 4-Eyes.

[bluemax]

Next step was to begin the disassembly, tagging, and bagging of all of the various parts.

While the basic rear end itself was bare metal from the factory, there are several components that were plated; rotors, adapter plates, caliper mounting brackets, brake hoses, tags, etc. The key is to try and determine what the correct finish was during the disassembly. Typically you can see the original finish when you remove the hardware.



Removing the 8mm Torx screws that attach the brake hoses, parking brake cable bracket, and lower shock mounting bracket was the hardest part of this job. All but one had to be drilled out and retapped.

[wraithracing]

That rear axle looks to be in great shape IMHO for a car that was daily driven in Chicago.
I would guess it didn't see many if any winters when it lived in Chicago.

I like your dolly too. That's a neat design!

Trey

[bluemax]

Next step is to begin cleaning all of the various parts and pieces to determine what can be reused and what will have to be replaced.

For the "bare metal" components, I typically bead blast, epoxy prime, and then paint the required color.

For the "plated" components, I degrease and use my tumbler to clean and polish in preparation for the plating. Same as painting, it is all in the prep to get the quality finish you want. If you have a plated part with minor surface rust, rather than use an abrasive material like the bead blast cabinet, I have found the EvapoRust product to be very successful.

Here are pictures of the rear end after sand blasting and a coat of epoxy primer.

[bluemax]

That rear axle looks to be in great shape IMHO for a car that was daily driven in Chicago.
I would guess it didn't see many if any winters when it lived in Chicago.

I like your dolly too. That's a neat design!

Trey

It was a daily driver for the first 10 years, I even have the receipts where he changed to winter tires each year. The undercoating protected most of the parts on the under carriage. I did have to repair some rust on the front fenders behind the bumper mounting brackets ("z" brackets) and I have replaced numerous parts that were too far gone to save; i.e. front fog light housings, rear upper control arms, etc.

[roush235]

Looking good, keep the info & pics coming. This is going to be an excellent learning experience for all of us who are watching, and I am confident it will turn out great.

[bluemax]

Looking good, keep the info & pics coming. This is going to be an excellent learning experience for all of us who are watching, and I am confident it will turn out great.

Ha! Now I have to live up to your expectations!

[vascj]

So nice to see threads like this. A great illustration that these cars are entering a new phase. Thanks for taking the time to present the work. Reminds me of restoring the rear on my 69 SCJ. Best of luck!

[bluemax]

I elected to go with a primer and top coat vs. trying to protect an original "bare steel" finish was that it will be easier to maintain on an occasionally driven car. While I don't typically drive long distances, I do recall a few years ago attending the MCA National in Pensacola and having to drive through a thunderstorm to get there.

Anyway... after the epoxy primer was applied, I replaced the axle bearings, seals, and pinion seal. The axle seals were not leaking prior to the tear down, but the metal portion was badly pitted from the rust. I elected to change the bearings since I had the axles out anyway.

National 5707 Axle Bearing
SKF (CR) 13992 Axle Seal

I used the SKF (formally CR) seal because it more closely resembled the oem seal vs. the National seal.

The pinion seal was leaking and needed to be replaced. This was my first time at replacing a pinion seal and long story short, I ended up having to replace the crush sleeve after I over tightened the pinion nut trying match the preload.

B7A-4662-A Pinion Spacer
National 3604 Pinion Seal
389546-S100 Pinion Nut

I used the National brand seal because the lip configuration is closer to the original design.

The pinion spacers (crush sleeves) and nuts are still available from Ford and cheaper than sourcing from NPD.

[bluemax]

Time for the top coat.

I have a collection of pictures from very low mileage cars (including Daniel Carpenter's) and from these it is obvious that the third member developed surface rust at a much faster rate than the axle tubes.

This is a picture of Daniel's '85.5 1C Comp Prep with only 379 miles.



You can see that the axle tubes and rear end cover are bare steel, while the third member is bare cast iron. So I want to try and recreate a subtle difference between the two materials.

First step was to mask off and paint the axle tubes. I used Eastwoods Detail Gray for this. I think the shade looks very close to bare steel. I prefer to use a spray gun for this vs. spray can because I feel I get a smoother finish.

Next I used Eastwoods Spray Gray for the cast iron, but I feel the contrast between the two colors (bare steel to bare cast iron) was too drastic.



So, I custom mixed my own color with a 2:1 mix of Spray Gray to Detail Gray. Unfortunately Eastwood does not sell the Spray Gray in quarts any more... I have requested, so maybe if others do as well, they will offer it once again.



I painted the axles with the same mix.

[83GTJIM]

This may be a silly question, but maybe not since it has been in MCA shows. With the rest of the car undercoated, do you ultimately plan to undercoat any of the rear end to match the rest of the undercarriage? Or will it all go away eventually? Beautiful work by the way!

[bluemax]

This may be a silly question, but maybe not since it has been in MCA shows. With the rest of the car undercoated, do you ultimately plan to undercoat any of the rear end to match the rest of the undercarriage? Or will it all go away eventually? Beautiful work by the way!

Great question!

According to MCA rules for under coated cars:

"Everything must be covered except drive shaft, differential housing, exhaust, steering rack & linkage, suspension parts & springs."

So, obviously there will be some variation on how precise the under coating was originally applied. In my case there was under coating on the axle tubes and the rear end cover, but not the cast iron third member. I even have some under coating on the steering rack... not pretty.

To answer your question, I do plan to remove the under coating over time. It is actually coming off fairly easily with "bug and tar" remover.

Thanks for the kind comments!

[Ken P]

Here is the driver's side rotor on the 86 CP I sold to Kendal with 10,213 miles. I have some other pics of springs etc.

[bluemax]

Here is the driver's side rotor on the 86 CP I sold to Kendal with 10,213 miles. I have some other pics of springs etc.

Nice picture of the two "push on spring nuts". Little detail that you don't typically get to see unless your in Thoroughbred Class.

Obviously these get tossed when the first brake job is done!

[rodster]

Looks great bluemax! Thanks for posting.

[JTurbo]

Looks awesome!

[bluemax]

Now for the fun part, putting everything back together!

The rear end cover was originally stamped bare steel. In my case it had been covered in undercoating, which protected it from rust, but sometime in the past was damaged on the lower lip, probably from improper jack placement.



I elected to find a nice replacement vs. trying to repair the original. Cover was cleaned, bead blasted, epoxy primed, and painted the same color as the axle tubes; Eastwood Detail Gray. The oem bolts were bead blasted and Manganese Phosphated to the original finish. I also replated the ID tag clear zinc. The assembly line paint mark was duplicated with a Markal paint stick.

[86GT2r]

Nice write up.
Thanks.

[roush235]

Matt, terrific work. Great write-up with excellent pictures. The results are outstanding. Having visited with you and traded information, I had a pretty good idea you would be "setting the bar" with respect to detailing a rear axle. Hoping I will get to see you and the car at a MCA show this year.

[shorangerbird]

The pinion spacers (crush sleeves) and nuts are still available from Ford and cheaper than sourcing from NPD.

-ya. NPD sources them from Ford. also we can still get the drum/rotor/axle stud spring nuts. a good bit of the 'little stuff' is still availiable. if its a car i'm perfectionist about, i go back to the microfische or OSI catalogs to get the original part number and its supersessions to run on locator to see if there any hidden out there...

[vascj]

Nice write-up. I typically like the finishes to remain natural, no painted metal finishes. Its alway a trade off between seeing slight surface rust and pretty painted surfaces. I believe most of the very high end restorers actually prefer to restore using original unprotected surfaces to allow for surfaces to age naturally allowing for graceful patina to occur. Personally I prefer to see original casted surfaces that have a little "ageing" like the original finishes on Daniel' s undercarriage. I guess it's just a matter of personal preference.

[1986Saleen]

Very nice work! Please continue documenting your work - it will make all our restorations better in the future! Are there additional paint blobs/marks present, like the examples above? Do you plan to reproduce those?

I understand what vascj is saying as well. It's really a tough choice/balance. If you were trailered, thoroughbred, or unrestored, unpainted natural finishes would be expected. But, for concours DRIVEN cars, replicating natural finishes with paint is probably the best way to go. I'm getting ready for a complete brake job, and have spent the last several weekends painting new calipers, rotors, etc just like you're doing.


I'll be watching your work closely. While my 86 Saleen is an unrestored & undercoated car, I'm careful weighing the whole preservation vs restoration thing myself - I'm too OCD to lightly accept weathered-looking parts, but also realize that I intend to stay in Concours Driven.

Thanks for posting!

[rodster]

....
The rear end cover was originally stamped bare steel. In my case it had been covered in undercoating, which protected it from rust, but sometime in the past was damaged on the lower lip, probably from improper jack placement.

......
The oem bolts were bead blasted and Manganese Phosphated to the original finish.

......
The assembly line paint mark was duplicated with a Markal paint stick.

My 84 SVO has a different style stamped cover, the lip is just 90° not rounded like yours. ?? Bolts look different too. ??

Have the same damaged lip tho' and also found a similar assembly line marking.

[79mustangcobra]

Good write up! Love the detail - thanks for posting!

[bluemax]

My 84 SVO has a different style stamped cover, the lip is just 90° not rounded like yours. ?? Bolts look different too. ??

Have the same damaged lip tho' and also found a similar assembly line marking.

Rod, please post some pics so we can see the differences.