Lower control arms

[MAStuart]

On an original leaf spring car. That material is the outer bushing. This is the bushings in the outer part of the rear lower control arm where it attach the upright. There are two of them in each arm and there is a seal on each side of each bushing. Is it oilite or some kind of bronze?

Also I hear the shaft that goes thru them was chrome plated. Was this a hard chrome ?

I don't think there was any grease zerks anywhere so how does this joint get lubed?

I was thinking Dan would know.

Always trying to learn about original cars
Mark

[CompClassics]

The bushing is the same as the material used in the leaf spring eye, the leaf spring pivot bolt is grooved and has provisions for a grease fitting though. I believe it is an oil-lite bronze type material. I have no idea why AC would have not had provisions for a means to lubricate this area, the 427s had lubrication points in these areas.

[Dan Case]

Originally Posted by MAStuart

This is the bushings in the outer part of the rear lower control arm where it attach the upright. There are two of them in each arm and there is a seal on each side of each bushing. Is it oilite or some kind of bronze?
Mark

Spreadsheet tables don’t paste into forum posts well. If somebody can tell me how to attach a file that can still be opened I will post the list of Cobra rack and pinion chassis service parts I compiled circa 1992 as general information. I have sent the spreadsheet file to several original Cobra owners recently so I think a few owners are still doing their own wrench work. Some of the original bushings and bearings are still common industrial items.

The original AC Cars rear lower vertical link pins were chrome plated. On street cars they were lubricated during assembly at AC Cars and that was it. To relubricate them required disassembly. I have had three cars apart rear suspension wise and only one had damaged chrome plating at it was a car driven in a state that salted its roads in the winter. To make replacements I bought chrome plated precision ground shaft material as used to build hydraulic cylinders. Shelby American had their own drawing version to make their own in the race shop.

[MAStuart]

Hi john. I have a spring drawing that someone sent me. It is from ac cars and I am not sure what time frame it is from. It states the spring bushing is phosphorus bronze. Also see Dan Case post on the spread sheet.

Mark

[Dan Case]

Originally Posted by MAStuart

Hi john. I have a spring drawing that someone sent me. It is from ac cars and I am not sure what time frame it is from. It states the spring bushing is phosphorus bronze. Also see Dan Case post on the spread sheet.

Mark

f.y.i.....it is real important to shorten commerical bronze bushes to match the width of the spring eye each goes into. You want the thrust bearings to work against the steel spring eye and not the bronze bush ends. As a side note if the bushes extend past the eye it can be incredibly hard to get the thrust bearings in.

Using a brass pilot tool to help align and hold everything helps a lot. Here's my drawing for the front spring eye tool to fit original spring pin bolts. This is too long for easy use in the rear.

[MAStuart]

Dan thanks for your reply. I see you got the spread sheet posted ......good info.


I was just machining the parts that the bushings and seals go into. I am building two sets of rear control arms for a Daytona Coupe. There is some conflicting info out there on the size of the bore where the seal goes. The plans I am working off of show the bore to be 1 inch another drawing shows .999 I just ordered some seals 7410, 7408 and a 312518 that is direct replacement for one of the other two seals. I also had a 7411 seal ordered but canceled it when I saw it was for a bigger bore.

I read your spread sheet and saw it calls for the 7411 seals. I bored the parts at 1 inch and thought any of the seals above listed would work. I could rebore my parts another .005 and use the 7411 seal.

Have you ever seen where someone has installed grease zerks in an otherwise stock setup?

Mark

[Dan Case]

Originally Posted by MAStuart

Have you ever seen where someone has installed grease zerks in an otherwise stock setup?

Mark

My information is based on stock street cars the way AC Cars made them. Racers made all kinds of modifications over the years, so many that finding completely original pieces is difficult.

Yes, I have seen vintage racers with a couple of different grease fitting schemes for rear lower vertical pins.

Also worth noting, since you are going after a racing configuration the RLS 12 rear hub bearings don't apply. For road racing, Shelby American modified rear vertical links and converted them to taper roller bearings for rear hub axles.

[MAStuart]

Thanks again Dan. Lots of good hard to find info here

I thought about grooving the bushing in an x pattern and adding a zerk. I don't think I will now because the way they came looks to hold up pretty well.

Mark

[rsk289]

I believe the original bushes for the rear lower wishbone outer pivot pin were a DU bearing, which is supposed to be self-lubricating.

https://www.ggbearings.com/en/products/metal-polymer/du

I stand to be corrected by Dan!

I know of some folk with Cobras and Aces in Europe who have machined Vesconite to do the job instead, with some success:

https://www.vesconite.com/prod/hilube.htm

Its origins are in the mining industry, I believe.

[MAStuart]

rsk289 yes that is the bearing 12DU16 listed in Dan's spread sheet. Link to spread sheet Common Rack & Pinion Cobra (leaf spring chassis) Service Parts

[MAStuart]

Well now that was painless. Called the local Motion industries gave them the Garlock number and seal numbers and they were there the next morning. I asked how this joint was lubed. Now things make sense. These bearings can be run dry. So thanks to the replies to this thread another problem on my build has been solved .


By the way the bearings were cheaper than the seals.

Mark

[rsk289]

Originally Posted by rsk289

I believe the original bushes for the rear lower wishbone outer pivot pin were a DU bearing, which is supposed to be self-lubricating.

As noted!