Rust under Upper control arm

tfowler9 · Sep 18, 2024

I decided to upgrade my front suspension and steering components. I have had the car since the mid 80's. Finally time to change after 40 years. I bought the entire kit from CJ Pony Parts. I have all the old components off the car. Just cleaning up before I install the new parts, I was surprise at the amount of dirt, stones grime under the upper control arm. I clean it out and found this (attached) there is no rust anywhere on the car. It is garage kept and rarely out in the rain. I believe it has been there since I bought it. Looks like a design flaw allowing the accumulation. Don't think it is a structure issue, but still a surprise when I found it. Anyone else seeing this.
Something else - the idler arm that came with the kit is a two piece unlike the original. And does not have the elongated hole like the original (see attached). The holes on the new piece do not line up with the car. I am going to have to drill out the part to make it fit. CJ POnu Parts do not indicate that at all on their website when purchasing the kit?

Tom

Sheriff41 · Sep 18, 2024

I'd repair the shock tower while it's apart, even if it was just to weld in some reinforcing where the rust holes have formed. Consider finding a different parts source in the future. Just my opinion.

73pony · Sep 18, 2024

Also. That Idler Arm will not work correctly. The geometry is wrong. Rare Parts makes the correct one for our cars. I believe the part number is 20250. +1 CJ is not my first or even 10th choice.

Steve McMahan · Sep 18, 2024

Agree with @73pony, the Rare Parts guys are the only ones with a correct idler arm. Concerning that newfound rust, that’s not an uncommon issue. The designed drain hole was insufficient and many of us have found rust there. I would clean it out the best I could and weld a patch there. Make sure the drain hole is large enough for the future.

Flatback72 · Sep 19, 2024

Yeah, throw away that idler arm. I bought one the same as that with the packaging marked as for a 71-73 Mustang but it was clearly a different geometry than the original.

I ended up buying this one instead (link below) from West Coast Classic Cougar which side by side had the same geometry as the one that I had pulled out of the car:

https://secure.cougarpartscatalog.com/71idler.html?sessionthemeid=26

rcadd1ct · Sep 19, 2024

I used the Opentracker roller idler.

Really helped make the steering be smooth and precise

Definitely address the rust before it gets worse.

tfowler9 · Sep 19, 2024

Flatback72 said:
Yeah, throw away that idler arm. I bought one the same as that with the packaging marked as for a 71-73 Mustang but it was clearly a different geometry than the original.

I ended up buying this one instead (link below) from West Coast Classic Cougar which side by side had the same geometry as the one that I had pulled out of the car:

https://secure.cougarpartscatalog.com/71idler.html?sessionthemeid=26

Thanks for the response....this is just a great forum, best of all the Mustang Forums. I have tried to contact CJ Pony tech group and they give me the runaround. The kit also came with the inner and outer steering rods. They are shaped different than the originals I removed. Wonder if they will work when I purchase the correct Idler Arm?

basstrix · Sep 19, 2024

They sell bushings for the idler arm, you may want to look into rebuilding what you have. Rock Auto sells them for both ends. Pay attention to bushing diameters if you go that route...I believe there are different versions of the bushings.

tony-muscle · Sep 19, 2024

The shock tower integrity is important for the suspension so fix/reinforce. Unfortunately Ford designed this depression under the A-arm that collects all the stuff the tires pick up. There are drain holes at each end but with time these clog and then water puddles in the depression leading to rust. It is always a good idea to keep those drain holes open. I would clean at least once a year.

Hemikiller · Sep 19, 2024

That rust is pretty typical. The pocket was supposed to be filled with seam sealer to allow water to run out the two notches - which didn't happen all the time. I'd cut and patch as needed, your rust isn't bad at all considering what I usually see here in the northeast.

Many of the replacement idlers have been wrong for ages. The one that was on your car is also a replacement. You could replace the bushings, or get the Rare Parts unit. West Coast Classic Cougar carries the arm.

https://secure.cougarpartscatalog.com/71idler.html?sessionthemeid=26

The tie rod ends should be ES387R for the outers, ES2004 for the adjusters and DS791 for the inners.

73Rosco · Sep 20, 2024

tfowler9 said:
I decided to upgrade my front suspension and steering components. I have had the car since the mid 80's. Finally time to change after 40 years. I bought the entire kit from CJ Pony Parts. I have all the old components off the car. Just cleaning up before I install the new parts, I was surprise at the amount of dirt, stones grime under the upper control arm. I clean it out and found this (attached) there is no rust anywhere on the car. It is garage kept and rarely out in the rain. I believe it has been there since I bought it. Looks like a design flaw allowing the accumulation. Don't think it is a structure issue, but still a surprise when I found it. Anyone else seeing this.
Something else - the idler arm that came with the kit is a two piece unlike the original. And does not have the elongated hole like the original (see attached). The holes on the new piece do not line up with the car. I am going to have to drill out the part to make it fit. CJ POnu Parts do not indicate that at all on their website when purchasing the kit?

Tom

While you have the upper arm off, really check the top of the frame. I am from Canada and the top of my frame was gone. If there is any holes I would get some Ospho or rust encapsulator and coat the inside of the frame in that complete area. If you don't, 5-10 years down the road you will be replacing the frame like I am. I was told to cut part of the lip off to allow the dirt to get out. Then weld up the remaining frame. There are companies that sell the reinforcing structure for this part.

Good luck.

tfowler9 · Sep 21, 2024

Top of the frame? Where the coil spring sits?
Can you give the name of the company and the part name? I think that would help me understand it better.
Thanks Tom

Francfort · Oct 6, 2024

How will you say its going so far?

tfowler9 · Nov 9, 2024

Hemikiller said:
That rust is pretty typical. The pocket was supposed to be filled with seam sealer to allow water to run out the two notches - which didn't happen all the time. I'd cut and patch as needed, your rust isn't bad at all considering what I usually see here in the northeast.

Many of the replacement idlers have been wrong for ages. The one that was on your car is also a replacement. You could replace the bushings, or get the Rare Parts unit. West Coast Classic Cougar carries the arm.

https://secure.cougarpartscatalog.com/71idler.html?sessionthemeid=26

The tie rod ends should be ES387R for the outers, ES2004 for the adjusters and DS791 for the inners.

Thanks again for everyone's help. Thought I would post the before and after!

Rust under Upper control arm

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