Rear suspension upgrade for towing

I have a 2002 Crown Vic and I’m going to be doing a fair amount of towing over the next year with it. Not heavy-duty. Class II range (3500#) at most, such as large UHaul closed trailer. The car rides pretty low anyway (stock springs and shocks) and when the trunk is full even lower. So I need a moderate amount of load leveling.



I’m leaning toward something like a Monroe Load-leveler because it’s automatic leveling and a fully engineered solution. But I’ve read they ride very harsh when unloaded and I’m not having much luck finding them. The air-bag spring helpers seem to be the common solution now (Ride-Rite or Air Lift) but it seems to me that just puts a heavier spring in contention with the same old shocks to dampen it.



Anybody have experience they’d like to share? Particularly for Crown Vic or similar style car. SUVs don’t have the same ride height issues and who could tell if one of them was riding harsher anyway?

You’re going to have to compromise somewhere. If you expect to control the bounce of your load with h/d shocks, then that’s what you’ll need to learn to live with when daily driving with no load. Put h/d shocks on the front too so your trailer doesn’t cause front end bounce as well.
I like the AirLift air spring for the best of both worlds.

I have towed trailers with rear drive Oldsmobiles, Buicks, Impalas and Caprices. You can either put in new heavy duty springs, like on the police or trailer towing package, together with HD shocks. That will let you tow a modest trailer without having to go to a load distribution hitch.

If you just want to put in HD shocks, you will have to go to an expensive load distribtion Class III hitch system to keep the rear from sagging too much.

As far as the ride is concerned, the three cars I’ve had with HD suspension all rode very well and were better handing on twisty mountain roads. So, I’d go for the HD rear springs and shocks. It’s relatively cheap to buy since many were built that way. Make sure the shop knows what they’re doing and the stuff really IS HEAVY DUTY!

Adjustable air shocks might be a consideration.

Many Vics came with rear “air-ride” suspension with automatic load leveling. But pulling and installing these parts would be quite a job…It would be easier and probably cheaper just to find a Vic with this option and the HPP option installed. A 3500# tow will be a little much for a Vic…

An HPP Crown Vic or Grand Marquis is a good idea, but they can be tough to find. If you can find an LS with rear air suspension, you can install heavy duty air springs pretty easily. The HPPs also have bigger anti sway bars, stronger front coil springs, dual exhaust (=15 hp) and a lower axle ratio. The latter will help you towing and is pretty easy to swap in as well. Stock is 2.73. Common on police cars and Mustangs are 3.27 and 3.55. It is probably not worth changing unless you go to 3.55. Sway bars are pretty easy (inexpensive) to add or change. Just make sure that you do it in a balanced way to avoid over or under steer. You can find them in salvage yards for well under $50. Just buy new end links. There are no easy cooling upgrades and you probably won’t need them. Dual exhaust components you can add to your existing system if you can find a set at a salvage yard, but the police cars don’t have the resonators.

You will get lots of advice from owners at www.crownvic.net. It is a good resource for you anyway. Another good resource for info about shocks, springs and stabilizer bars is http://www.p71interceptor.com/. The CNG vehicle springs are the stoutest that Ford installed, IIRC.

I have a feeling you want to do this on the cheap and another car is out of the picture. The air-in-coil inserts are the best solution because it allows you to adjust the spring rate to the load. I think it is better extremely stout springs. They will make you handle very poorly unloaded. Air-lift shocks are not such a good idea because the shock mounts are not strong enough to support the extra stress.

If you buy them on line, the Ford police/taxi shocks are a good buy. You can find info at the above links. If you are really going to near 3500#, you should seriously consider a Class III weight-distribution hitch.

You will need an isolator for the trailer lights. Keep your speed sane and make sure the trailer brakes are working correctly.

Thank you all for your thoughts. They really helped. That is an important point about the shock mounts not being intended to carry the weight of the vehicle. I have thought of that, but didn’t really have any info on it.

BTW, 3500 is the far upper limit. 1500 is much more like what I would be pulling, about 4 +/- times a year, so I really don’t want to go overboard. Pretty sure I’m going to go with the Air-Lift or Firestone Ride-Rite (air-bag-in=spring) solution. If I find the shocks are too whimpy to handle the increased spring rate, then I’ll upgrade to the police shocks.

Thanks again for all the responses. Happy Trails to all.
- DropTopDelta88 (guess what I drive for fun)