How to Fix Awful Ride - 1991 Grand Wagoneer

[Brynjminjones]

Thank you, I like the idea of removing the shocks. I'll give it a go if I get a chance!

I tried loosening the bolts on the leaves to free everything up then re-torque, but I couldn't get the bolts to budge.
I decided to give up as it seemed too much like hard work

I did manage to pry apart the leaves and lubricate everything though.

Afterwards, I think there has been a marginal improvement but nothing dramatic.


I took it down some dirt roads to test and it actually rides pretty nicely on the bigger bumps, it's just smaller imperfections on the road where it seems unnecessarily harsh.

One question I've got - Is it right for my front shackles to rest in this position?
Waggy Front Shackle by Brynjaminjones, on Flickr

[letank]

Thank you, I like the idea of removing the shocks. I'll give it a go if I get a chance!

I tried loosening the bolts on the leaves to free everything up then re-torque, but I couldn't get the bolts to budge.
I decided to give up as it seemed too much like hard work

I took it down some dirt roads to test and it actually rides pretty nicely on the bigger bumps, it's just smaller imperfections on the road where it seems unnecessarily harsh.

One question I've got - Is it right for my front shackles to rest in this position?
Waggy Front Shackle by Brynjaminjones, on Flickr

flat springs, they do not provide any spring action, they should have a slight arch, also with the amount of rust, I suspect , yes suspect that the bushings are rusted solid


this is the only pict I have on file, you can see some arch




found a better one, but this is with a 2" lift

[rang-a-stang]

Yeah, I agree. Those springs look done. If you look at the main spring on the driver side, it looks slightly bowed upward between the shackle and the start of the second spring. Your passenger side spring looks pretty rusted, too; To the point where they look like they are not parallel anymore.

[babywag]

Yep...that spring pic says it all.
Get some new ones.

[Mikel]

I would agree that the springs look yielded, but the spring rate should not have changed. Lots of factory springs with no arch, or even negative arch (Chevy, Dodge, Ford...). Most FSJs here have yielded original springs and drive fine.



I would still try removing the shocks. I would try lubing the leafs too.

[Brynjminjones]

Damn, that's the wrong answer, didn't you all get the memo?
You were supposed to say "those look great, they absolutely don't need replacing!!"

Looks like it's time to start pricing up some replacements, although I may still try removing the shocks in case they're also an issue.

[Brynjminjones]

Okay, so now I'm looking at replacement leaf springs and it feels like I've opened a can of worms!

My GW has 7 leaves on the front, 5 on the rear.

The Jeep parts manual says I need part number J536 2953 for the front, and J536 2956 for the rear.


I went straight to BJ's first. Their imported fronts are 4 leaf. The USA ones are 6.
The imported rears have 3 plus overload, the USA ones are 4 leaf plus overload.

I then looked at RockAuto, which does have some with the same number of leaves. However, I cross-referenced the Dayton 97-400 front leaves, and they are J536 2951 , which is actually the part number for the standard duty front springs in a J10/20, not a GW. It's a different part number so I'm guessing they must actually be different.

I couldn't find a cross reference for the rears at all!


Can somebody point me in the right direction to find direct replacements for what I have currently?

Also, as I'm in the UK, are there specs available anywhere so I could have some made up? I've had a look but not much success.

[J76137]

I agree with letank and rang-a-stang. Those springs actually have a negative arch in the front. If you look closely you can see that the front of the top spring is bending over the next lower spring. Judging from the amount of rust on them the whole spring pack is likely sticky and worn.

[Brynjminjones]

Yes, I think you're right. Here's how the rear of the spring looks, it's even worse.

IMG_20200526_135246 by Brynjaminjones, on Flickr

I'm sure the rear are shot too. This is how much it sags towing a ~1000lb trailer:

IMG_20191004_123140 by Brynjaminjones, on Flickr

[wiley-moeracing]

you need to order up a new set of springs, front and rear. I would think you could find a local spring shop there that may be able to build you a new set?

[Brynjminjones]

Thanks, I'm looking into it now to see what I can find!

There's a local shop with a great reputation that should be able to build some for me, but I don't know what specs to give them.

I've also found some Crown springs in the country for a good price. Are stock replacement Crown springs any good?

[wiley-moeracing]

They will work if you can find them.

[rang-a-stang]

I had a set on mine and they were a little soft for my liking but sounds like that may be perfect for you!

[DarkMonohue]

I'm going to splice and rearrange quoted pieces so that we can discuss springs and dampers separately. Let's do springs first.

I know the springs are worn, but I'd guess that they'd become softer with time rather than firmer.

I'm not sure whether springs become softer when they sag, or simply lose ride height. Either way, rocklaurence makes an excellent point:

My guess is that your bottoming out on the bumps due to sagging springs. With good springs you should have 3-4" of space between the axle tube and the bump. If your at 2<" it'll transfer all that energy into the frame.

This is really important. The cushiest springs and shock absorbers in the world will ride like hell if the axles are bouncing off the frame every time you hit a pebble. Did you get a chance to measure that distance between the tops of the axle tubes and the bottoms of their respective bumpstops? It's worth a look so that you can better understand what your problems really are before you start changing things.

I'm sure the rear are shot too. This is how much it sags towing a ~1000lb trailer...

Unless you have the car loaded up with a whole lot of heavy cargo, or the trailer tongue weight is far in excess of 150 lb (typical tongue weight for a 1000-lb trailer), it should not be sitting that low in the back.

There's a local shop with a great reputation that should be able to build some for me, but I don't know what specs to give them.

I've also found some Crown springs in the country for a good price. Are stock replacement Crown springs any good?

For my money, I'd take the Jeep to the local spring shop and let them look it over in person. I'd bet that they can get all the information they need just by looking at your springs. Odds are good a trained, experienced eye will see right away where the leaves have changed shape and what sort of arch they originally had.

Besides that, if you do have a problem with local work, you can walk in and make yourself a pest until you reach a resolution. It would be a lot harder to do that if you aren't happy with the Crown springs, especially if any time has passed. You can do a quick search here to learn of Crown's reputation. It ain't universally positive.

Are these Monroe Gas-Magnums known to be firm shocks, and would changing them likely sort my problem?

Ride quality is subjective, and shocks are only one part of the system, but Monroe's shocks seem to have a general reputation for being softer than comparable products from other manufacturers. That said, anything labeled "heavy duty" may be stiffer than you want if ride quality is a priority. I put Gabriel Max Control shocks on my J20 and wish I'd gone with something less robust. Even for a pickup configured for fairly heavy loads, it's extremely harsh unless very heavily loaded (e.g. a thousand pounds or more).

I took it down some dirt roads to test and it actually rides pretty nicely on the bigger bumps, it's just smaller imperfections on the road where it seems unnecessarily harsh.

That does seem to point toward shock absorber damping that allows the suspension to respond to bigger/harsher impacts, but not smaller ones. At the risk of oversimplifying a fairly sophisticated science, your shocks probably have more damping than is appropriate for your vehicle and its usage.

Sorry, but it sounds like you're probably in need of new springs to correct the sag and restore full suspension travel as well as more appropriate shocks to get the ride comfort back.

[Brynjminjones]

DarkMonohue, thank you for that incredibly helpful answer!

I will read through and answer properly when I've got a bit more time this next couple of days