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Mustang II front shocks not "tall" enough

16K views 8 replies 4 participants last post by  Centerline 
#1 ·
I have searched the Knowledge Base and previous posts but did not find an answer to my problem.

I just took delivery of a 1939 Ford Panel truck, with what I assume is a "standard" hot rod set up of 350 Chevy and Mustang II front suspension.

I am a complete amateur and this is my second post, so bear with me as I explain my situation.

Inspecting the car underneath, I noticed the bottom of the right front shock was not attached to the lower control arm. After searching for and locating the bolts, I could not re-bolt the shock because the hole/"pipe" at the bottom had been dented ( probably due to the shock swing back and forth aganist the A arm ) and so the bolt would not go through.

So I went to my local auto parts store and bought two new Mustang II front Monroe shocks. Upon installing these new ones, I noticed they were not as "tall" as the old ones. The cast "tube" is the same, but the metal rod which moves up and down in the tube and attaches to the upper control arm is approx 1" shorter than the old shocks.

The only way I could install the shocks was to omit the rubber bushing on top of the control arm. I kept the bushing below the upper control arm, but if I used both bushings, the threaded part of the shock does not stick up enough for me to bolt it to the upper control arm.

My friend who knows much more about hot rods than I do commented it has tubular set up with drop spindles. I assume this means the distance between the upper and lower control arms may be greater than standard Mustang II geometry, and thus, I would need a taller shock.

This is where you come in. :mwink:

I have searched and searched the Internet with no luck. I am just stupid here? Do I need someone with more muscle to extend the shock for me? Or do I need better more expensive shocks than the $12.99 ea I purchased at Murray's? If so, what are your suggestions and where do I get them? Do they make taller shocks for Mustang IIs that are dropped???

Thank you in advance for your help.

BTW, here's a pic of the car for reference:
 
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#2 ·
The fact that you have lowered spindles will not make the shock too short. My guess is the springs are too stiff for your setup and won't allow the suspension to compress enough to get the shock on. You can check this by looking at the lower "A" arms. They should be level with the road. If they're not the springs are either still new or too stiff.

I say this because people constantly make the mistake of using springs that are too stiff when installing a Mustang II IFS systems. They don't do their homework and don't understand the weight requirements of a street rod so they just guess or listen to a buddy that knows nothing about this IFS system.

The original Mustang II IFS was designed to have the engine mounted directly over the cross member. That's a lot of weight for the suspension to support so it had pretty hefty springs, even in the 4 cylinder models. When you mount one of these suspensions in a street rod the engine usually sits with the crankshaft dampener over or slightly behind the crossmember. When the engine is moved back that far it changes the weight distribution (moves it to the rear) quite a bit. This means that lighter springs are required for the front suspension since more of the weight is being supported by the rear suspension. Generally speaking a small block powered street rod will only need stock Mustang 4 cylinder front springs. Even with a big block you don't need more than the 4 cylinder with air springs. I run a 750 lb hemi in my truck and a 454 in my pro-street car and both use the 4 cylinder springs.

To fix your problem try this. Have a buddy come over and stand on the running board to see if his weight will compress the suspension enough to get the nut on WITH the rubber bushing. If the threads are close to begin with a 200 lb. person should be able to compress the suspension enough to allow you to get the nut on with no problem. If the springs are new they will settle in a few hundred miles and you won't have that problem again. If they are too stiff then the ride will not be as comfortable as it should be and you may have some alignment problems. The solution in that case is to install the correct springs.

Good luck.

Centerline
 
#3 ·
Thanks Centerline!- I also found out some interesting info about the shocks....

I looked at the shocks I took off, which were stamped with the number 32118.

The shocks I bought were 20814.

I checked Monroe's reference book at the auto parts store, and it did list 20814 for Mustang II 74-78.

But when I checked Monroe's website this morning, it lists 32118, for Mustang II 74-78.

So I'm going to try the 32118 shocks.

The springs aren't that new, my father had it built several years ago and drove it from LA to Sacramento, so I'd hope they'd be softened up by now.

If the new shocks dont work, I will try out your suggestion of new springs.

BTW, I was told you're not supposed to stand on the running boards by other panel truck owners. Is this BS?
 
#4 ·
Don't know if that's BS or not. I don't have that problem with my 53 pickup. Like I said earlier, one sure way to tell if the springs are too stiff is to check the lower control arms. They should be level with the ground. If they're not, the springs are too stiff.

Centerline
 
#5 ·
To fix your problem try this. Have a buddy come over and stand on the running board to see if his weight will compress the suspension enough to get the nut on WITH the rubber bushing. If the threads are close to begin with a 200 lb. person should be able to compress the suspension enough to allow you to get the nut on with no problem.
This is not going to help as with the shock installed in this method, it will always be at it full length travel and will not dampen the conrol arm movement and will most likely lead to shock, shock mount or suspension failure. The shock needs to be at mid-travel when installed.

Is this a stock MUST II crossmember or a kit? If a kit, you need to contact the manufacturer and find the correct PN. If stock, as mentioned, the springs may be too stiff. Are the lower conrol arms parallel with the road surface? Yes or no. If yes, you need to go to the back of the shock catalog and find a shock with the proper travel and mounting. If no, you need to change the spring rate.

There are (or were) mounting extensions to increase the shock travel. It's Mickey Mouse but may get you out of the current problem.
 
#7 ·
Not sure if kit or stock Mstang II- any way to tell?...

Not sure if its a kit or stock. Asked my father, he doesn't know. If he can find the paperwork, I may have to call the shop where it was installed ( years ago in Southern California ) and see if I can find out.

Nevertheless, I did get the 32118 shocks just here at lunch, which seem to match the 32118 shocks I took off. The one is maybe 1/8-1/4 inch shorter, other seems spot on. Much closer than the 20814's I bought yesterday. Is there any way to force them to extend when installing?

I will look at the lower control arms tonight when I get home to see if they are parallel to the ground.

I am hoping by replacing the shock with the exact same one as I took off will be an even swap and everything will be good.

One thing I would like do, the car was set up in CA, which has infinitely better roads than Metro Detroit. Our best roads are still crap. So anything I can do to improve and smooth out the ride would be ideal...

Thanks again for your help:D
 
#8 ·
Report: Replacement shocks on

Put the "correct" 32118 shocks on last night.

Much to my surprise, the 20814 shocks also had 32118 stamped on them.

And they were also about the same overall length.

But the distance between the cast painted tube and the bowl shaped bushing inherent to the shock was greater on the new ones.

I had no trouble getting both bushings on both sides of the upper control arm.

My guess is the newer shocks were just that- newer, and less stiff. Both were Monroe, just purchased at different auto parts stores, in different boxes 20814 vs. 32118. Besides the 32118, there was another number, almost like a serial #, which is different on all three sets ( orig as delivered, 20814 set, 32118 set. )

And yes, the lower control arms are parallel to the ground, so I assume the springs are good.

Thanks again to everyone for your help. It rides significantly better, now I will look at what I can do to the rear suspension.:D
 
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