Idler arms. Anyone use a Rare Parts 20250

Bentworker · Mar 5, 2017

Above is a picture of an OEM arm on top and mystery import on the bottom.

Anybody try the Rare Parts brand idler arm?

How about the Opentracker roller one?

I am not too crazy about the mystery import one I have. One of the bushings seems like it is not pressed in all the way. Looking at other repo ones online it seems like the bushing might be pressed in that's way by design.

I might try the Rare Parts one, or I might get new bushings for the stock one I have.

Thanks!

Peter

Stanglover · Mar 5, 2017

Above is a picture of an OEM arm on top and mystery import on the bottom.

Anybody try the Rare Parts brand idler arm?

How about the Opentracker roller one?

I am not too crazy about the mystery import one I have. One of the bushings seems like it is not pressed in all the way. Looking at other repo ones online it seems like the bushing might be pressed in that's way by design.

I might try the Rare Parts one, or I might get new bushings for the stock one I have.

Thanks!

Peter

Peter, this was posted on recently. I purchased one from NPD part #3355-1 pro grade. It is a good part geometrically, but the top hole needs to be slotted upward. This is noted with the instructions if I remember. Bit of PITA, but the idler works well and has grease nipples top and bottom. I believe it is US made, but not sure now of the brand.

Just as a suggestion.

Geoff.

Bentworker · Mar 6, 2017

I ordered up the 3355-1A from NPD. I'll post pictures once it shows up.

Stanglover · Mar 7, 2017

I ordered up the 3355-1A from NPD. I'll post pictures once it shows up.

3355-1A is for a 1970. It may be the wrong geometry for a 71-73. Also taking a second look at your picture, the one you say is OEM may not be. I think it's been changed before because the definitely original one I took off my 71 had no grease nipples at all, just rubber bushings. It was for a manual s/box and I was changing to P/S, but comparing the two, the fitment was the same. (I don't have an original P/S idler arm to compare, so you could well be right with your part.)

In a previous thread ( not sure how to locate it on here) we had gone through the geometry issue. Basically, a member was concerned because the old and new part didn't look the same. It was explained that as long as the center lines of the 2 bushings were the same distance apart as the original and the angle was the same plus the top of the drag link bushing was at the same height relative to the center of the bottom bolt hole, it mattered not where the position of the bottom bushing was. in other words, the arm between the bushings was a different shape.

The 3355-1 Pro grade was exact relatively other than the shape of the arm and having to slot the top hole. Why it was not made correctly is beyond me unless it is also used on applications other than Ford. I don't think there was a manufacturer's name on it.

Anyway Peter, I hope that the part you ordered will work out. I'm curious if it will.

Geoff.

secluff · Mar 7, 2017

While most of the other unibody Fords used different arms for M/S and P/S, the 71-73 Mustang used the same idler arm for both applications. I don't recall seeing any of the OE Ford arms with grease fittings. The Ford part numbers (in order of supersession) are D1ZZ-3350-A, D1ZZ-3350-B, and in 1975 the final replacement D3ZZ-3355-A. A pink paint daub or stripe was the color ID.

I found the post Stanglover was referencing and he provides some excellent info concerning geometric angles and how the dip stick length is also needed for the correct part! https://www.7173mustangs.com/thread-idler-arm-question--25289

Stanglover · Mar 7, 2017

While most of the other unibody Fords used different arms for M/S and P/S, the 71-73 Mustang used the same idler arm for both applications. I don't recall seeing any of the OE Ford arms with grease fittings. The Ford part numbers (in order of supersession) are D1ZZ-3350-A, D1ZZ-3350-B, and in 1975 the final replacement D3ZZ-3355-A. A pink paint daub or stripe was the color ID.

I found the post Stanglover was referencing and he provides some excellent info concerning geometric angles and how the dip stick length is also needed for the correct part! https://www.7173mustangs.com/thread-idler-arm-question--25289

Steve, thanks for finding that post. The part Roadwarrior is showing is incorrect as the relative height from the top of the drag link bushing is off by quite a bit. Slotting the bottom hole may not be the way go, but I don't have time right now to double check what part he had. I know the USA made part I have from NPD does match up exactly other than that damn top hole that does need to be slotted.

Too funny about that darn dipstick!! (but a reader would have to go back to that earlier post to get it)

Geoff. aka stanglover

Don C · Mar 7, 2017

I agree that the Moog idler arm appears to be incorrect. I looked it up on their website and it is the one they show.

Because the support end bushing/pivot is moved away from the bracket by the angle it is attached to it will change the steering geometry. The OEM bushing/pivot is in line with the bracket.

The ones shown by OMS, NPD, and NAPA (especially their Rare Parts line) all appear closer to the OEM style.

Stanglover · Mar 7, 2017

I agree that the Moog idler arm appears to be incorrect. I looked it up on their website and it is the one they show.

Because the support end bushing/pivot is moved away from the bracket by the angle it is attached to it will change the steering geometry. The OEM bushing/pivot is in line with the bracket.

The ones shown by OMS, NPD, and NAPA (especially their Rare Parts line) all appear closer to the OEM style.

I'm not sure who makes the NPD part ,#3355-1, but they do sell Rare Parts steering parts. I bought a new pitman arm and it is marked with the diamond shape logo and the R/P for Rare Parts. I guess a call to NPD would answer that question if someone had the desire to do so.

73pony · Mar 7, 2017

Hmmm. I have the moog one sitting in the basement. I will have to check it out tonight and compare to the original on the car.

red351 · Mar 7, 2017

Aftermarket Roller idlers will no help center the steering from turns as oem was used for. Rollers idler may create bump steer problems

Bentworker · Mar 7, 2017

This is an interesting find, an OLD Moog sheet showing a K-8165 arm, seems to be obsolete now.

The NPD 3355-1A is a Rare Parts 20250. We shall see what it looks like in a few days... I hope.

Bentworker · Mar 12, 2017

The Rare Parts 20250 arm came! Not super excited about it at first glance. It is actually a Rare Parts 20218 casting that they have machined to work on a 71-73. It has an offset in it that isn't apparent in a side profile pictures that are online. I'm sure it will work fine, but it does look different enough that it will catch an eye under the car. As far as beefiness and quality of machining it seems great. I will get it fitted on the car in a couple weeks or less.

More pictures of the arm that came off the car. It is looking more like an old MOOG.

Holes in the car. 3/8" diameter, just shy of 2 3/4" on center.

Rare Parts 20250 arm on the right. Notice the weird offset.

Application sticker from NPD on the Rare Parts bag.

Old arm off the car on the top (maybe MOOG?)

Mystery arm in the middle I ordered up about 8 years ago.

Rare Parts 20250 arm on the bottom.

Stanglover · Mar 12, 2017

The Rare Parts 20250 arm came! Not super excited about it at first glance. It is actually a Rare Parts 20218 casting that they have machined to work on a 71-73. It has an offset in it that isn't apparent in a side profile pictures that are online. I'm sure it will work fine, but it does look different enough that it will catch an eye under the car. As far as beefiness and quality of machining it seems great. I will get it fitted on the car in a couple weeks or less.

Old arm off the car on the top (maybe MOOG?)

Mystery arm in the middle I ordered up about 8 years ago.

Rare Parts 20250 arm on the bottom.

That 3355-1A (listed for a 1970) looks nothing like the 3355-1 that is supposed to be for the 71-73 even though as I said before, the top hole has to be slotted upward toward the end. I know that one works on my 71 and the steering center return is excellent. If I were you, I'd send it back and reorder the 3355-1. Geometrically, it matches the original if not visually. Trust me on this one my friend.

Geoff.

If I get time, I'll take a picture of my idler arm and post it for you. Trouble is the car is in my 1 car garage, hard to get jacked up and it's turned freakin cold again!!

Bentworker · Mar 18, 2017

This is the one on my parts car.

Looks almost exactly like the one that Geoff talked about. I might send the Rare Parts one back... waiting for some more parts to get powdercoated and I will mock it up.

Otto · Mar 23, 2017

I would highly recommend the Proforged idler arm, which is guaranteed for "a million" miles, part #102-10076. It appears to have been discontinued by the company but I'm sure there are some still floating around. It is classified as a severe duty part and while I haven't driven it in a severe fashion, I am very happy with it. It is also greasable. I used the rare parts #20250 for years and I was happy with it. Even though it was shaped differently, mine maintained the factory geometry. I even have a new piece (#20250) I bought before finding the proforged piece. I put that one in storage in case I ever need it.

klinton994 · Apr 1, 2017

Above is a picture of an OEM arm on top and mystery import on the bottom.

Anybody try the Rare Parts brand idler arm?

How about the Opentracker roller one?

I am not too crazy about the mystery import one I have. One of the bushings seems like it is not pressed in all the way. Looking at other repo ones online it seems like the bushing might be pressed in that's way by design.

I might try the Rare Parts one, or I might get new bushings for the stock one I have.

Thanks!

Peter

Just a heads up. Last week I was entertaining the idea of replacing the pitman arm on my 71 Mach 1. At the local NAPA auto, the only brand pitman arm they could get is Rare Parts. I inquired about the country of origin. The counter person looked up that information and told me it is produced in Taiwan.

On another note, I will try to take pics of those spindles in the next couple of days.

Clinton

klinton994 · May 16, 2020

Coming in on this thread a few years late. I purchased the moog idler arm for my car. The mounting holes did not line up. Has anyone found an idler arm that bolts up correctly without having to modify/slot the bracket, and is in the correct position and height to work with steering linkage?

ty

Bentworker · May 16, 2020

I ended up keeping the rare parts idler arm in my car. Geometry was good and it seems stout. However it does not “look correct”

klinton994 · May 16, 2020

I ended up keeping the rare parts idler arm in my car. Geometry was good and it seems stout. However it does not “look correct”

Did it bolt correctly to the body without modifications? I’m also in need of a pitman arm.

Idler arms. Anyone use a Rare Parts 20250

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