A shocking message

Ride height is controlled by the springs, not the shocks. Raising the back end of a vehicle using shocks is not a good way to do so. Shocks aren't supposed to carry the load of the vehicle, the springs are. Putting that sort of stress on the shock absorber mounting points might cause them to fail.

You need to evaluate how much weight you're trying to move around and compare that figure to the GVWR. It sounds as though you're overloading the vehicle, which has a nasty tendency to bite you on the a** when you're least expecting it. You need to find out what the tongue weight of the trailer is, as well as its overall weight. You also need to find the weight of the cargo, including the passengers. Compare these figures to the ratings in the owner's manual. If you're anywhere near the maximums indicated, you can assume the vehicle is being overloaded. In hilly terrain, this can have disastrous and perhaps even fatal consequences.

You can sometimes improve things with 'helper' leaf springs to pick up the ride height. This might alleviate one factor in your situation, but note that this modification wouldn't do *anything* to help, say, braking performance, another serious factor (which might be alleviated with trailer brakes, for example). And with a 3.0L/4 speed engine/trans combination, you can safely assume that you will significantly shorten the life of the drivetrain if you're overloading the vehicle. There's apparently not a lot of tolerance in the design for this; 'tis one of the reasons why people on this newsgroup find themselves rebuilding blown transmissions.

So my suggestion is that you take a very serious look at what you're trying to do with this minivan, and try to decide if it's really up to the task you've presented. Good luck.

--Geoff

If you can, try moving some of the stuff to the trailer, but do not put excessive weight in front of the trailer axle otherwise you will still have the problem.. putting excessive weight behind the axle is treacherous.. you can get devices that will measure downforce on towing hitches. they are useful for distributing weight properly acrros the whole train..

I don't do any towing, but I had the rear springs in my 94 GC beefed up with an extra leef in each rear spring.

The reason I did it was that the original springs are SHIT!!!!!!! Even with the slightest load in the read of the van - even a small bike rack and two bicyckes - the rear of the van would go WAY down. To the point that driving onto a ferry deck at low tide would cause the back of the van to bottom out! :((((

That extra leef was AMAZING! The shop told me I will now have an extra

400 pounds of tongue weight above factory spec.

And I went camping a few weeks ago with the van FULLY LOADED. The height of the rear end did not even budge more than an inch! In fact, the van actually looks "jacked up" - which it is not. (Why would anyone jack up the rear of a front wheel drive?? lol!).

I and very happy with the upgrade, and I am sure that I will never have any problem towing small trailers for short periods of time (like for moving and stuff), should I choose to do so.

hth

You may never have any problem towing, etc., but be prepared to start wearing out front rotors and brake pads considerably faster than you have to this point. I had a '92 T&C and I, too, was not happy with the rear leaf springs and excessive sagging with hardly anything in the back. I did some research and found that Air-Lift had a system available that would compensate for this when installed. Bought it, installed it and solved the problem --- or so I thought.

The recommended minuimum pressure was 25 lbs. but I felt every little bump. More pressure gave a harsher ride. No pressure was still stiff but mostly acceptable so I left them on. I then started going through rotors and pads as if they were paper but the rear shoes and drums rarely showed any wear. Found out the reason was the "brake proportioning valve". Without the rear end lowering as weight was loaded the valve was not allowing the brake system to compensate. As a result I was essentially stopping using only the front brakes whenever the van was loaded or I was towing a Coleman camping trailer. I removed the Air-Lift system and then traded the van in '96 for a T&C LXi that had the height-adjustable shocks.

Is that really true about the proportioning valve? I did not think they changed their proportioning action due to weight or positional changes. Are you sure that the extra wear was not due to the fact that you started towing and carrying those heavy items more (rear brakes aren't going to wear as fast as the fronts anyway, so you wouild have noticed the fronts waearing out faster)?

Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")

Yes, that is really true about the proportioning valve. I had the van for almost four years three of which had the Air-Lift system. I towed the camping trailer a total of three weeks over the three years and I had the van full of people and kids that would probably total six weeks of those three years. The van had close to 80,000 miles on it when I traded it for the '96. In that time I replaced the front brakes and rotors six times and traded it with the original brakes on the rear. The last time I had the front brakes replaced I asked why the van had worn out the front so many times. The technician explained that the proportioning valve was there to compensate for heavier loads so the rear brakes would be applied equally as more weight was added. He further explained that with the Air-Lifts keeping the rear end level I was essentially fooling the system into thinking there was no added weight hence the majority of brake pressure was absorbed by the front brakes. Made sense to me then, makes sense to me now. I leave it up to you and anyone else to draw your own conclusions. I only posted the response based upon my experience.

I am with you on this one Bill... I remember in the old days when front disks were new on cars in the US , Chrysler at least used to put a valve in the front brake circuit,,, think it was called a "metering" valve.. don't remember for sure,, long time ago), haven't worked on many cars in the last

30 years or so.... and it's purpose (again as I remember) was to balance the front and rear wear by restricting flow to the front disks until (30 lbs or so?) to over come the return springs on the back shoes before the disk pads were applied.. there of course was also a proportioning valve on the rears also.

Just guessing by this memory, I suspect that "light and often" braking would contribute to the extra front wear without this device, but I really don't know.. I am sure Stern will have something to add.

I remember my father in law bought a Saab 96 (1969 in 1969)and that car really needed such a device as it went through pads about every 5000 miles, but that is another story.

Some one with an old service manual may be able to comment,, as I think you had to put a clip on this "metering valve" in order to bleed the brakes with the old block the pedal down part way and let it drip method...(then again all from memory)

Anyone?

That would go along with the normal proportioning valve action - it would have two slopes (in curve of front pressure vs. rear pressure) and a changeover point, called a "split point", at the vertex of the two slopes.

I'm really skeptical about that part of the tech's explanation - but I very well could be wrong.

Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")

I am NOT here to debate - I only posted from experience. I only know what happened with my van. I only posted as a "heads-up" FYI piece. I haven't had the van for 8 years. Whether that was the cause for going through front brakes and rotors the way I did no longer matters. I do know that for the first year of ownership I put about 29,000 miles on the van and replaced the front pads and rotors at 28,000 miles. I then replaced front pads and rotors five more times over the next three years (after the Air-Lift installation) which averages out to every 10,400 miles.

BTW - In posting this reply I remembered why I finally removed the Air-Lift system. I called Air-Lift to explain what had occured with me and was told that they had discontinued this item. They had discovered through their testing and calls from consumers that it caused problems with the braking system and ride quality on these vans.

RP

Nor I. I'd really like to know the answer about the proportioning valve sensing vehicle level - hoping someone in the know would post.

Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")

I know nothing about Chrysler minivan brake systems but I can tell you that that is exactly how the prop valve works on a FWD VW so it is not outside the realm of possibility. (especially since Chrysler took a few pages out of VW's notebook over the years.)

nate

I haven't looked at either of my vans that closely, but my last two pickup trucks have a proportioning valve that senses the load. It is a rotary valve mounted on the rear axle that has an arm that connects to the bed of the pickup. As the truck is loaded, it is supposed to bias the brakes more and more towards the rear. So, in this case having air bags or other load leveling devices would defeat this proportioning system. I wouldn't be surprised that minivans would have this, but I've never crawled under mine to take a look.

Matt

Never heard of it !... thanks Matt !!!!,, going to have to crawl under the van now for sure,,,, well maybe not..

Ted

I'd really like to know the answer about the proportioning valve

I didn't realize that proportioning valves had gotten that complex (or sophisticated, depending on your point of view) even if it's so for only a limited number of appliations. I learned something. Thanks!

Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")

I still haven't felt like looking under my minivans, mainly because I can't get under then without jacking them up, but I did go pull out my service manual (genuine Chrysler manual). From the description and the pictures, it does NOT appear that the 1996 minivan has a load sensitive proportioning valve. I do not see any linkage on it that connects to the rear axle. Just two lines going in and two coming out.

Matt

Look at this link under "mechanical proportioning valves" for a description of the height/load sensing valves.

Matt

Thank you Matt !!!!

Man did I learn a bunch... and why the new cars (FWD to be specific) don't have the "metering" valve...been wondering about that one.

Enough people like you around I just might get smart before I die.... .. .. .. nah,, I know there isn't enough time left for that anymore,, probably never was... but,, 1 less thing I am totally ignorant about !!

Ted

Interesting. Thanks!

That article indicates that the typical height sensing valves are adjustable for changes in ride height. Perhaps that is the answer for those who add helper springs or air shocks. However, stiffening the suspension will decrease the sensitivity even if it is adjusted to compesate for neutral height.

Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")