Why is my ride quality so TERRIBLE?

[jgkurz 52]

Hi Folks, I mentioned this topic on another post but it wasn't the focus so I want to create a new thread. I recently got my 69 Mach 1 back on the road after a minor restoration. I tore the car apart shortly after the initial purchase so no real experience. While the car was apart I replaced the front and rear suspension. The front is working very well with grab-a-track springs, Shelby drop and Maier Bilstien front shocks. I'm very happy with the front suspension.

 

The rear is a whole different matter. I lowered the rear about 1/2 inch with new Global West 125lb rear leaf springs, added Viking double adjustable shocks, and installed CalTracs's with a solid from eyelet. I also installed Global West's Del-A-Lum shackle kit with the correct tension on the shackle bolts. I went somewhat soft on the leaf springs to help ride quality. The Viking shocks are set to the recommended clicks for the best ride possible. All this trouble and the car still rides like a truck. It's miserable if the road has any bumps. I don't have any perspective on what a 69 Mustang fastback ride quality should be so maybe I'm expecting too much. The rear of the car is very stiff which makes for a harsh ride. My wife and daughter don't like riding in the car because it's so rough. I can't even imagine how the recommended 200lb Caltrac leaf springs would have been like. I've done everything I know how to do. Please let me know if you have any ideas. THANK YOU.

 

EDIT: The springs are 150lb Global West L10's not 125lb.

 

Signed,

Desperate

[1969_Mach1 333]

Harsh ride is usually never an issue on these cars.  That spring rate for the leaf springs is fairly soft.  The spring bushings you installed will transfer more road bumps, cracks, etc. into the body of the car.  Other than that is sounds like something is bound up.  I am not certain if the CalTrac's would affect the ride.  There are others here using CalTracs that will probably chime in.  What tire and wheel size are you using?  

 

I use the Grab-A-Trac 5-leaf mid eye rear springs (195 lb./inch) with Urethane bushings and Grab-A-Trac 720 front coil springs, (600 lb./inch) in my 69 Mach 1.  It rides firm but not so harsh you don't want to drive the car.

[jgkurz 52]

Thanks for the response. I am running 15" Magnum 500's with 255/60-15 BFG's on the rear. I hope other Caltrac folks chime in. Just so I'm clear, the car rides and handles fine on a smooth surface. The rear suspension just won't absorb any bumps in the road. It's almost feels like I'm hitting the bump stops but its no where close.

[Rsmach1 71]

I would try replacing the rear del-a-lum bushings with stock rubber, that should soften things up a bit. Also what wheel/tire are you running out back, and at what psi?

[jgkurz 52]

I would try replacing the rear del-a-lum bushings with stock rubber, that should soften things up a bit. Also what wheel/tire are you running out back, and at what psi?

 

I run 255/60-15 BFG's in the rear at the recommended pressure. The del-a-lum setup might be the cause but I hate to swap them out until I hear from other folks running the same setup. I liked them for use with my Caltracs. Supposedly they help the suspension move more freely to absorb bumps.

 

^{(disregard the attached pics. They are getting attached automatically. I have no idea where they are from)}

[TX427Cobra 19]

Everyone has different perspectives, this is mine (from building race cars and offroad trucks):

 

-  Springs don't define ride quality, they define ride height.  A heavier spring will resist roll and compression.  A lighter spring will allow more roll and compression.

 

-  Shocks are usually the culprit when all new components ride poorly.  A soft spring coupled with a firm shock is commonly a bad combo that results in a harsh/rough ride.

 

-  Remove the rear shocks and drive it up the street and see if its still harsh.  If not, then dial the rear shocks back in one click at a time until you are happy.  

 

-  My experience has been that Bilsteins are harsh out of the box.  Just because they are on the front and you aren't feeling it in the steering wheel doesn't mean they aren't contributing, they are.  

 

-  As stated above I suspect the aluminum bushings are a big contributor.

 

Just my 2 cents....

[jgkurz 52]

Everyone has different perspectives, this is mine (from building race cars and offroad trucks):

 

- Springs don't define ride quality, they define ride height. A heavier spring will resist roll and compression. A lighter spring will allow more roll and compression.

 

- Shocks are usually the culprit when all new components ride poorly. A soft spring coupled with a firm shock is commonly a bad combo that results in a harsh/rough ride.

 

- 600 fronts and 125 rears on a unibody car for street use seems like a mismatch to me. I bet if you remove the rear shocks and drive it up the street you will be shocked that its still harsh. If not, then dial the rear shocks back in one click at a time until you are happy.

 

- My experience has been that Bilsteins are harsh out of the box. Just because they are on the front and you aren't feeling it in the steering wheel doesn't mean they aren't contributing, they are.

 

Just my 2 cents....

 

Edit>> The comments about delalum bushings are relevant, they are likely adding to your problem.

I appreciate your input. I'm not a suspension guy so I relied on Global West to recommend a leaf spring for my needs. (Big block, Caltracs, 90% street-10% strip) I sure hope the shocks are not the issue. The Viking's are crazy expensive. I'll disconnect them and see if it makes a difference. I don't need to drive the car, I'll just push down on the bumper. My front Bilsteins are custom valved but they are performance shocks so not tuned for a soft ride.

 

Regarding the Del-A-Lum shackles, I knew they'd be less forgiving to vibration and noise but I didn't think they make the suspension stiffer. I have the nuts fairly loose but maybe they are still binding. I might pull the springs down and see if they are binding.

[Rsmach1 71]

When you say recommended psi are you talking the 35 max listed on the tire? If so you can air em down to 30 no problem, that might help your ride quality somewhat.

[barnett468 418]

.

set the compression damping on the rear shocks to 0 and the rebound to maybe 1 then drive it.

 

if it is still stiff, make sure the springs are not binding . . if they are this is your primary problem.

 

if not then remove the rear shocks and drive it carefully, the damping may just bee too stiff.

[jgkurz 52]

My shocks are set almost at the lowest setting for both compression and dampening. It's got to be the shackles or the springs binding.

[1969_Mach1 333]

If your shackles are not binding, I was curious, did you install the CalTracs at the same time as the leaf springs?  Or, were the CalTracs installed at a later time?  I am not familiar with CalTracs, but I wonder if there is something in the geometry preventing the front section of the leaf spring from deflecting for normal driving.  As the leaf spring flattens during compression the distance from the spring eye to the spring locating pin at the axle increases.  Normally the rear shackles permit that.  Is something now preventing that from occurring on the front section of the spring? I have seen pictures of CalTracs, but I cannot envision how they permit the spring to operate as it normally would under normal driving.  I wonder if that is why Global West suggested such a soft leaf spring?

[Ridge Runner 1,112]

If your shackles are not binding, I was curious, did you install the CalTracs at the same time as the leaf springs?  Or, were the CalTracs installed at a later time?  I am not familiar with CalTracs, but I wonder if there is something in the geometry preventing the front section of the leaf spring from deflecting for normal driving.  As the leaf spring flattens during compression the distance from the spring eye to the spring locating pin at the axle increases.  Normally the rear shackles permit that.  Is something now preventing that from occurring on the front section of the spring? I have seen pictures of CalTracs, but I cannot envision how they permit the spring to operate as it normally would under normal driving.

This would be a very good possibility ,if the bars were welded in with the rear end in droop /up on jack stands with the rear end sagging ,that would cause binding .the bars need to be installed with the full weight of the car on the leafs .

[superduty69 11]

How do you have the CalTracs adjusted? Do you have preload in them or a gap? Did you set them up with your weight in the drivers seat?

[jgkurz 52]

How do you have the CalTracs adjusted? Do you have preload in them or a gap? Did you set them up with your weight in the drivers seat?

 

 

I don't have any preload on them so no gap. The bolt sits on top of the spring when the Caltrac bar is loose. What is the better setting for ride quality, some gap with preload or no gap and loose bar?

[1969_Mach1 333]

If you cannot find anything wrong have you thought of removing the Caltracs and see how the car rides?

[RPM 1,190]

My shocks are set almost at the lowest setting for both compression and dampening. It's got to be the shackles or the springs binding.

He recommended removing the shocks to eliminate them from the problem. Telling us they are set almost at the lowest setting does not eliminate them from the problem. Hopefully the problem is in the caltracs.

[superduty69 11]

I don't have any preload on them so no gap. The bolt sits on top of the spring when the Caltrac bar is loose. What is the better setting for ride quality, some gap with preload or no gap and loose bar?

Preload is when the cross bolt on top of the spring is tight to the spring and is applying pressure to the spring. Preload will stiffen the suspension.

 

Since you are having a problem "I" would unhook the shocks, loosen the front eye bolt and the shackle bolts. Adjust the CalTracs so that the cross bolt is off of the spring as much as you can and bounce the rear of the car.

It should bounce freely and a lot, like 4-5 inches.

 

Did you grease all the bolts and bushings when you installed them?

Did you have the bolts in the shackles and front eye tight? They should be just snug, nylock nuts are the best in these applications.

^^^ these are important^^^

 

Hook back up shocks and set to full soft, both settings. Bounce the car again to see if it is better.

Adjust the CalTracs to 1/4"-3/8" gap and drive the car. And see what you have.

 

Sometimes it is better to go back to the beginning and start over. Something is bound up and by going over everything it is easier to find the issue.

[jgkurz 52]

RPM, I haven't removed the shocks, yet... I'm 90% confident they are not the problem. I tested them when I put them in two weeks ago. In hopes of a quick fix I went directly to the Caltracs.  I spoke to BuckeyeDemon last night in addition to reading the posts here. I think you all got me pointed in the right direction. I had my Caltracs adjusted wrong plus I over-tightened my front eyelet. They are now loosened to allow movement but with locking nuts. I need to put some miles on the car to be sure but I think it may be fixed. The car will never be a quiet/soft ride with the aluminum front eyelet bushing and the Del-A-Lum shackles but it should be far better if the suspension is moving properly.

 

Superduty69, Thank you for the great details on adjusting he Caltracs. I briefly messed with them last night by putting the bar in a neutral loose position. Based on your advice, I will tighten the bar so the pivot is pulled to the back and the cross bolt has at least a 1/4 gap. I should probably add grease to all the bolts and bushings as well. 

 

Thank you all!  I think I got this licked.

[jgkurz 52]

Well I definitely got the ride quality resolved but I introduced another issue. My leaf springs are new from Global West and were only suppose to lower the car .5-.75". I wanted a stock ride height after I put larger tires in the rear. It sounded like a good plan but now my car sits too low in the rear. After the Caltracs were adjusted correctly and the various binding was releaved the car settled a bit more on the springs.  Here's a pic. Are springs suppose to be flat like mine? I'm thinking I need to re-arch them a bit.

 

Also, they are 150lb springs not 125lb as I stated above. 

 

[1969_Mach1 333]

I haven't seen a new spring that flat.  I don't know if it's a new unrelated issue or a continuation of the first.  Are they de-arched standard eye springs or standard arch mid-eye springs?  If they are de-arched standard eye springs that might be what you get.  Maybe check with Global West.  If it were my car I would have initially installed the leaf springs without the Caltrac's so you have a baseline for the rear suspension.  Then if any changes occur after installation of the Caltrac's you'll have a better idea of the cause.

[barnett468 418]

He recommended removing the shocks to eliminate them from the problem. Telling us they are set almost at the lowest setting does not eliminate them from the problem. Hopefully the problem is in the caltracs.

 

yup

[1969_Mach1 333]

I don't know what exactly the cause of the new issue.  But I am glad to hear I am not the only person suspicious of the Caltracs.  I just haven't been able to envision how they permit the leaf springs to operate as they normally would for normal driving..

[coz 108]

Never had any ride issues with my Caltracs.  They have preload on them and though a stiff ride they are not harsh. 4.5 mid eye leafs with KYB.  Also have more arch in the springs then what you show.

 

http://www.1969stang.com/g1/COZ-69Mach1/114_1420?full=1