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post #1 of 21 (permalink) Old 06-30-2019, 11:28 PM Thread Starter
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70 XL suspension

Hi again,
Suspension this time.
My XL has some sort of air suspension on the rear. In the manual it says Fords could have an auto levelling system with bags within the coils. Mine hasn't got that, but it does have 2 shockers with an air supply to them. In the manual this is the Lincoln system called superlift shockers.
It doesn't have the whole system, just the shockers with pipes to a shraeder valve in the trunk(No auto levelling system with onboard compressor). When I first found this I discovered there was nothing in them, so read about it in the manual and it said to test the shockers inflate them with 50-60psi them immerse them in water to check for leaks. I figured I'd just pump them up and see what happened. The cars rear end lifted up and stayed lifted, cool I thought, plus the stance was better looking with the back slightly higher).
Now... I have since had the front suspension control arm bushes replaced and now the front end looks slightly higher than the back.
Question is can I put more pressure into those shockers to lift it up more at the back? I don't want to blow them.
What sort of pressure do these shockers operate at?
Thanks in anticipation
Tony
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post #2 of 21 (permalink) Old 07-01-2019, 06:21 AM
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Re: 70 XL suspension

Sounds like aftermarket air shock kit.

When you install the new front bushings,
if you tighten the control arm bolts with the car jacked up and the suspension "hanging"
this puts stress on the bushings and causes the front to sit high.

You must tighten the bolts with the suspension at normal ride height,
ie; with the car sitting with full weight on the ground.
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post #3 of 21 (permalink) Old 07-01-2019, 07:03 AM Thread Starter
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Re: 70 XL suspension

Quote:
Originally Posted by galaxiex View Post
Sounds like aftermarket air shock kit.

When you install the new front bushings,
if you tighten the control arm bolts with the car jacked up and the suspension "hanging"
this puts stress on the bushings and causes the front to sit high.

You must tighten the bolts with the suspension at normal ride height,
ie; with the car sitting with full weight on the ground.
I didn't do it, a garage did.
I'll have to ask them

Any idea what pressure the rears should be run at?
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post #4 of 21 (permalink) Old 07-01-2019, 08:30 AM
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Re: 70 XL suspension

Quote:
Originally Posted by drov3r View Post
I didn't do it, a garage did.
I'll have to ask them

Any idea what pressure the rears should be run at?
I don't know what brand air shocks you have, but the Monroe Max Air kits say minimum 20 to 150 psi max.

Use whatever pressure (up to max) that gives the ride and height you desire.

The instructions (from memory) say the shocks can be damaged if run with 0 psi.
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post #5 of 21 (permalink) Old 07-01-2019, 11:51 PM Thread Starter
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Re: 70 XL suspension

Quote:
Originally Posted by galaxiex View Post
I don't know what brand air shocks you have, but the Monroe Max Air kits say minimum 20 to 150 psi max.

Use whatever pressure (up to max) that gives the ride and height you desire.

The instructions (from memory) say the shocks can be damaged if run with 0 psi.
Thanks, I'll have a closer look to see if I can work out what type is fitted.
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post #6 of 21 (permalink) Old 07-02-2019, 01:05 PM Thread Starter
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Re: 70 XL suspension

Quote:
Originally Posted by drov3r View Post
Thanks, I'll have a closer look to see if I can work out what type is fitted.
Had a closer look and after a good scrub up, spotted the Max Air lettering with some barely legible numbers. Tried to pump them up, but only got to 75psi ish. My compressor max output is 150psi. Might try running the pump for longer.
Does sit more level now, but I would have expected it to be the other way round, with the back slightly higher than the front (or am I thinking of drag cars here)
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post #7 of 21 (permalink) Old 07-02-2019, 01:33 PM Thread Starter
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Re: 70 XL suspension

Quote:
Originally Posted by galaxiex View Post
Sounds like aftermarket air shock kit.

When you install the new front bushings,
if you tighten the control arm bolts with the car jacked up and the suspension "hanging"
this puts stress on the bushings and causes the front to sit high.

You must tighten the bolts with the suspension at normal ride height,
ie; with the car sitting with full weight on the ground.
If I was to do this myself on the drive, what would I need to do?
Would it be a simple case of loosen the top and bottom control arm fixings with the weight on the ground, let it settle, then tighten them up again???
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post #8 of 21 (permalink) Old 07-02-2019, 06:14 PM
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Re: 70 XL suspension

Quote:
Originally Posted by drov3r View Post
If I was to do this myself on the drive, what would I need to do?
Would it be a simple case of loosen the top and bottom control arm fixings with the weight on the ground, let it settle, then tighten them up again???
Yes, loosen all the control arm fasteners in the front that use rubber bushings.

Before tightening, move the car back and forth say, 3 meters or so on a level driveway to get the tires and suspension to settle to their new position.

Make the final motion of the car going forward and apply the brakes firmly so the nose "dips" and come to a stop.

Re-tighten.
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post #9 of 21 (permalink) Old 07-03-2019, 02:04 PM Thread Starter
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Re: 70 XL suspension

Quote:
Originally Posted by galaxiex View Post
Yes, loosen all the control arm fasteners in the front that use rubber bushings.

Before tightening, move the car back and forth say, 3 meters or so on a level driveway to get the tires and suspension to settle to their new position.

Make the final motion of the car going forward and apply the brakes firmly so the nose "dips" and come to a stop.

Re-tighten.
Actually spoke with the mechanic tonight (he turned up at a classic meet we went to, remembered the car and spoke to me). So I told him what you said, and he said you can't do it like that because it would cock up the camber angles.
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post #10 of 21 (permalink) Old 07-03-2019, 02:08 PM Thread Starter
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Re: 70 XL suspension

Quote:
Originally Posted by drov3r View Post
Had a closer look and after a good scrub up, spotted the Max Air lettering with some barely legible numbers. Tried to pump them up, but only got to 75psi ish. My compressor max output is 150psi. Might try running the pump for longer.
Does sit more level now, but I would have expected it to be the other way round, with the back slightly higher than the front (or am I thinking of drag cars here)
Managed to get the pressure up to 130psi and now the car is pretty much level, looks better, and drives better.
Doesn't feel like I'm losing the steering so much under heavy acceleration either (which it did before).
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post #11 of 21 (permalink) Old 07-03-2019, 06:20 PM
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Re: 70 XL suspension

Quote:
Originally Posted by drov3r View Post
Actually spoke with the mechanic tonight (he turned up at a classic meet we went to, remembered the car and spoke to me). So I told him what you said, and he said you can't do it like that because it would cock up the camber angles.
He remembered the car, but is he familiar with the design of the front suspension?

NONE of the control arm (upper or lower) rubber mounted bushings are alignment adjustment points.

The caster and camber is adjusted by loosening the upper control arm SHAFT to FRAME mounting BOLTS.
You would NOT touch those.

The upper shaft bushings are retained by NUTS on each end of the shaft. Loosen those.

The inner lower control arm bushing is NOT an adjustment point either.
Safe to loosen and re-tighten that bolt.

Yes, it's likely things will shift slightly if you do this loosen/tighten procedure as I have outlined.

You should have the alignment checked and adjusted as needed after this, but it shouldn't be very far out.

The bad part.....

If the bushings were tightened with the car jacked up and the suspension at full droop, it WILL cause the bushings to fail early.
It puts a great deal of strain on those bushings to have them "holding the car up" like that.
As you have noticed, the front sits high, BECAUSE the bushings were tightened with the suspension "hanging".

You don't have to believe me.
I'm only 61 years old and have been a licensed mechanic almost my whole life.

I am also very familiar with these cars, having owned and been involved with restoration of several of them.

I suggest you get a repair manual specific to your model and year.
Especially read the chapter on front suspension.
There are reprints of the factory shop manual available.
A Google search will find them.
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post #12 of 21 (permalink) Old 07-04-2019, 09:14 AM
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Re: 70 XL suspension

It sounds like you did not replace the springs, just the bushings in the front suspension, so I would completely concur with Galaxiex in his assessment. The suspension needs to be taking the full load of the vehicle before the bushings are torqued down, which is likely the same requirement for just about every vehicle out there with these cast rubber type bushings. If you didn't install new springs, then the ride height should have been the same after the new bushings, as it was before. The bushings should not be under any static load.


Just jacking the rear up with the air shocks will also effect ride quality, but I think these cars look much better with a little rake from back to front. Those systems were intended for maintaining ride height and suspension travel when carrying heavy loads, not really for compensating for worn out springs. I still have to cut my front springs to get the front back down to where it was with the old springs and restore the previous stance.

1970 XL, 351W originally 2V, now 4V
670 Street Avenger, Edlebrock Performer intake, Comp XE262H, Flowtech Headers

Last edited by 70XL; 07-04-2019 at 09:25 AM.
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post #13 of 21 (permalink) Old 07-04-2019, 12:29 PM Thread Starter
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Re: 70 XL suspension

Quote:
Originally Posted by galaxiex View Post
He remembered the car, but is he familiar with the design of the front suspension?

NONE of the control arm (upper or lower) rubber mounted bushings are alignment adjustment points.

The caster and camber is adjusted by loosening the upper control arm SHAFT to FRAME mounting BOLTS.
You would NOT touch those.

The upper shaft bushings are retained by NUTS on each end of the shaft. Loosen those.

The inner lower control arm bushing is NOT an adjustment point either.
Safe to loosen and re-tighten that bolt.

Yes, it's likely things will shift slightly if you do this loosen/tighten procedure as I have outlined.

You should have the alignment checked and adjusted as needed after this, but it shouldn't be very far out.

The bad part.....

If the bushings were tightened with the car jacked up and the suspension at full droop, it WILL cause the bushings to fail early.
It puts a great deal of strain on those bushings to have them "holding the car up" like that.
As you have noticed, the front sits high, BECAUSE the bushings were tightened with the suspension "hanging".

You don't have to believe me.
I'm only 61 years old and have been a licensed mechanic almost my whole life.

I am also very familiar with these cars, having owned and been involved with restoration of several of them.

I suggest you get a repair manual specific to your model and year.
Especially read the chapter on front suspension.
There are reprints of the factory shop manual available.
A Google search will find them.
I like what you are saying, and I am more inclined to listen to yourself than some young upstart mechanic (who does seem to know what he is talking about mind). I do have the 1970 ford workshop manual which comes in 5 parts, unfortunately it doesn't mention torqueing up the suspension with the car on the ground. It just says torque it to the required value.
I am not totally sure of which fastenings to undo and re-tighten.
A picture would be fantastic.

Last edited by drov3r; 07-04-2019 at 12:33 PM.
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post #14 of 21 (permalink) Old 07-04-2019, 07:24 PM
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Re: 70 XL suspension

Quote:
Originally Posted by drov3r View Post
I like what you are saying, and I am more inclined to listen to yourself than some young upstart mechanic (who does seem to know what he is talking about mind). I do have the 1970 ford workshop manual which comes in 5 parts, unfortunately it doesn't mention torqueing up the suspension with the car on the ground. It just says torque it to the required value.
I am not totally sure of which fastenings to undo and re-tighten.
A picture would be fantastic.
This picture is from my 1966 Galaxie shop manual.

1970 is the exact same suspension design.

In fact, Ford used this same basic design from 1965 to the late 70's maybe even later....

The red arrows are the fasteners you would loosen and then tighten after moving the car.

The green arrows are the bushings that those fasteners secure.

The upper arm bushing retaining nuts are accessible from under the hood (bonnet).

For the lower arm bolt and nut, you will have to crawl under the car unless you have a drive-on hoist.
You could drive the front wheels up onto blocks or ramps to have more room to work.

Loosening these 3 fasteners on each side has no danger of cocking up the alignment,
but you should still have the alignment checked after this.

NOTE that there is no need to completely remove these fasteners.

Just loosen each of them a couple of turns.
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Last edited by galaxiex; 07-04-2019 at 07:37 PM.
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post #15 of 21 (permalink) Old 07-05-2019, 08:14 AM Thread Starter
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Re: 70 XL suspension

Quote:
Originally Posted by galaxiex View Post
This picture is from my 1966 Galaxie shop manual.

1970 is the exact same suspension design.

In fact, Ford used this same basic design from 1965 to the late 70's maybe even later....

The red arrows are the fasteners you would loosen and then tighten after moving the car.

The green arrows are the bushings that those fasteners secure.

The upper arm bushing retaining nuts are accessible from under the hood (bonnet).

For the lower arm bolt and nut, you will have to crawl under the car unless you have a drive-on hoist.
You could drive the front wheels up onto blocks or ramps to have more room to work.

Loosening these 3 fasteners on each side has no danger of cocking up the alignment,
but you should still have the alignment checked after this.

NOTE that there is no need to completely remove these fasteners.

Just loosen each of them a couple of turns.
That is absolutely fantastic, the only thing you could have done better would be to come over to the UK and do it for me.
Astounded by your great help and good response.
I will definitely be giving that a go, and I will report back on how different the car is.
Can't say thanks enough, but THANKS again.
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