67' 300 Shocks

Cortez

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I am tackling the drum brakes on my 300 and figure I should change the shocks while I am at it, any recommendations on shock options. Also has anyone used the HiJackers adjustable air shocks, I am considering those for the rear. As always thanks my C Body Bros...and sisters!!
 
I am tackling the drum brakes on my 300 and figure I should change the shocks while I am at it, any recommendations on shock options. Also has anyone used the HiJackers adjustable air shocks, I am considering those for the rear. As always thanks my C Body Bros...and sisters!!

Air shocks are usually not a good option for a C Body.

The steering geometry is such that if you raise the rear end of the car significantly, it throws the steering geometry off which will adversely effect handling and tire wear. If the back is sitting low under load, I would suggest a Monroe load leveler style shock or their equivalent to keep the car level.

Dave
 
Stay away from air shocks. If you need height in the rear replace the springs.

Shocks? Monroe' s KYBs... I used Bilsteins, a stiff ride but she' s tight
 
My own personal experiences must be different than some of y'alls, which I respect.

When I bought my '70 Monaco Bro, it had Monroe Load Leveler rear shocks on it. The rear end still sat low. The first owner had done some trailer towing with the car. I didn't know of any spring shops at that time, so my best option was air shocks. This was in '75 timeframe. I ended up with the Gabriel HiJackers. I got them installed and the air lines run and teed near the rear license plate. One line for both shocks. It took about 60psi to get the rear end up enough to level the car, no higher. Just to compensate for the rear leaf springs being "used".

The HiJackers have their regular shock section with the larger HD shock piston diameter and nice valving. What I was not expecting was the greater stability the rear end had in corners. Like a rear sway bar. As the car leaned to the outside, that side being compressed and with a common air supply to the other side, put more pressure on the inside rear wheel for better traction. I was very pleased.

Durability was very good. When the air bag started to seep, about 80K miles later, I got another set to replace them.

My '80 Newport had the factory HD suspension (the "no rear sway bar" HD suspension). It had done some trailer use, so it had some "Midas" air shocks on it. The bags were seeping, so I got some Monroe air shocks to replace them. Just need about 35psi as the rear springs are not sagged.

On the Load Levelers, you'll notice the assist spring is wound tighter in the middle than on the ends. That keeps the ride soft, initially, getting stiffer with more load. Compensating for "used" rear springs they will NOT, by observation. You'll not know they are there. As to increasing the load capacity? Not very much, from what I've seen.

Both the air shocks and Load Levelers are a "bolt-on" fix for the need for rear springs with an extra leaf or so, BUT my orientation is that the air shocks are the best option. There's more flexibility for the loading and still keeping the car level (up to their capacity).

The issue can be if a bag breaks with a loaded vehicle. The HiJackers have shields to prevent debris from getting to the bag whereas the Monores do not have shielded bags. Be that as it may.

In Ford's HD Trailer Package for their Country Squire/Sedan wagons, about 1970, they included rear air shocks in that package, BUT plumbed them separately. IF one went away, as I heard about from a local person, that side of the car "went down". If they had been plumbed together, the whole rear would have gone down. Neither is desirable, but one might be worse than the other one. So, paying attention to the rear air pressure IS important to help prevent sudden issues.

As an "aid", the air shocks seem to be the best option to me. With the Load Levelers, you get what you get. With the air shocks, you've got some flexibility of the amount of load you can add and still keep the car level. The need for minimum air pressure (usually about 30psi or so) is to keep the bags inflated and in place, I suspect, as that low pressure has no real affect on the car's levelness.

I will concur that using air shocks to raise the rear end of the car does affect the alignment geometry. It might be fixed on the car, but when you raise the rear of the car above specs, then the result is negative caster in the front end alignment. There can be possible stability issues with that much negative caster, although the steering effort would decrease a bit. Just NOT a good idea, no matter what!

Due to the size of the tube the front shocks go up into, the max shock piston diameter is usually 1", rather than the 1.375" for HD shocks. No clearance for anything bigger, so they make up the difference with the shock valving so everything's still balanced, f/r.

Back when the cars were newer, or in their "used car" era, there were many options for replacement shocks. Brands, piston diameters, etc. Now, I think almost everything is pretty much the same, other than whether the shock as low pressure, medium pressure, or high pressure gas in them. Monroe's MonroMatic used to be their basic shock, but now they have the larger pistons (when possible) whereas they all used to be 1" shocks. KYBs have a lot of good recommendations on them. Totally not sure about Gabriels any more . . . other than the air shocks.

I have no issues with using air shocks, even to compensate for sagged rear springs, but they were meant for temporary heavy load suspension aids. If you're going to haul heavy loads as a matter of course, get the rear springs themselves upgraded.

Enjoy!
CBODY67
 
My rebuttal to that is , if you replace the springs you will see a noticeable difference in the handling characteristics of the car. You will probably never notice a sag . With a full trunk , including a cooler and three kids in the back seat my springs hardly sag. They certainly never let the *** drag .

Replace the springs ...!!
 
My rebuttal to that is , if you replace the springs you will see a noticeable difference in the handling characteristics of the car. You will probably never notice a sag . With a full trunk , including a cooler and three kids in the back seat my springs hardly sag. They certainly never let the *** drag .

Replace the springs ...!!


I would agree, if you are dragging the bumper etc., fix whatever is wrong. Could just be failing spring bushings. If you looking to jack up the rear for appearances sake, you have the wrong type of auto.

Dave
 
It isn't sagging that bad at all here is a recent picture what do you all think

20180427_152300.jpg
 
It isn't sagging that bad at all here is a recent picture what do you all think

View attachment 185754

That looks like a pretty normal ride profile to me. Measure the pinch joint under the rocker 6" back of the front wheel well and 6" in front of the rear wheel well. (That would be the metal strip that hangs down from the rocker) They should be the same distance from the floor.

Dave
 
I like my air shocks. I keep just enough in them to make the car ride level when I have it loaded with crap, like when I go to Carlisle. To rebut the guys who say this is wrong, simply go to the FSM and look up the factory "load leveling" option that was available on most of our cars, '72 and up, and then come back and explain what the difference is between a factory installed load leveler and the pair I bought for $65.00.:poke:
 
Nothing, but most don't use them for that. They use them as a band aid for saggy or weak springs?
When were your springs replaced? :poke:
 
Never, but they only sag when the trunk is over loaded. Just like any car or pick up that is over loaded. And just barely... I guess I'm a nit picker about such things.
I've put enough money into the car already, I'm not going put springs in it when it doesn't need them.
 
I understand. It has been my experience that most 40 year old leaf and coil springs under a vehicle are not doing what they're supposed to do.
We don't realize how much suspension components have worn out until they are replaced. Once replaced we say " woah I should have done this sooner ".
 
Never, but they only sag when the trunk is over loaded. Just like any car or pick up that is over loaded. And just barely... I guess I'm a nit picker about such things.
I've put enough money into the car already, I'm not going put springs in it when it doesn't need them.
I' m gonna look under your car at Carlisle. We're gonna let the air out of the shocks. If your springs are flat or worse, you owe me a snow cone.
 
People are not understanding how these Monroe air adjustable shocks work. :mad:
They are not (!!) suitable for returning a car to a proper stance when the leaf springs are sagging from age.
The stiffness of the air shock is NOT constant throughout the change in its length. The more you add air, i.e. raise or lengthen the MONROE air shock, the STIFFER the shock. Stiffer!
The purpose of Monroe air shocks is to raise the car when there is EXTRA weight pressing down on the shock causing the *** to drag. Then pumping up the Monroe shocks to normalize the ride height is counterbalanced by the extra weight to normalize the ride.
Pumping up the shocks to normalize the height due to weak springs turns the ride into being that of a Conestoga wagon.
As far as the OEM air shocks, that's Apples and Oranges. Totally different in function and purpose. The ride height is MAINTAINED by height sensors.
The stiffness of the factory air shocks is tuned to give a normal ride height with good springs.
Add weight, the *** then sags, the sensors add more air to the shock and the the stiffness of the ride is the same as the shocks with less air and no extra load. In other words, Normal.
If you feel the ride is acceptable to YOU by pumping in air to the Monroes to counteract saggy springs, fine. You'd also be happy in an unloaded F- 450. Not me.

And I bet you still put wooden clothes pins on your fuel line to prevent vapor lock. :realcrazy:
 
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Here is a better pic, I dont think it looks that bad but I will get out there and measure tomorrow

20180510_181737.jpg
 
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