Suspension improvements input

[zona98]

I have a 1977 Jimmy High Sierra 4x4 with original just about everything (paint, interior, engine, etc.). I replaced the original spare tire two weeks ago. The truck is in excellent condition for its age.  My top priority is keeping it as original as feasible.

Two weekends back was the first off road trip. Tame forest road, but the road was in rough shape. It was a bumpy, tough trip on the truck. I assume the suspension is original. No lift.

Any suggestions that might help improve the suspension yet keep it predominantly original?

The truck is likely to be 85% weekend/car show cruiser, 15% tame overlanding.

I知 new to the truck and suspension discussions.

[Rapid Roy]

Welcome.

[75gmck25]

Assuming you want to keep it original, with no lift.  You are never going to get the "bumpy" part out of a straight axle suspension, but you can make it a little better.

If the original springs and bolts are not broken, you could replace all the spring eye bushings with new polyurethene bushings to tighten it up a little.  There are also bushings on the front anti-sway bar, if it has one (it was an option).  New shocks will probably help quite a bit if the truck is bouncy.  You can spend $25-$150 per shock, but I would probably stay in the $50-100 range to get decent quality at a reasonable price.  There are frequent specials on shocks, so shop around.  Installation is very easy.

Cab/body bushings are also probably worn and need to be replaced.   By now those rubber cab bushings may be compressed to metal on metal.  It won't help it ride better, but it will be quieter.

To tighten up the steering - You should replace the outer tie rod ends (the end that connects to each wheel), and the inner tie rod (or drag link) that connects the steering box to the steering.  Its also common to install a new rag joint in the steering, or convert to the Jeep steering shaft with a universal joint.  You can borrow the tie rod removal tool from the local box store and it will be much easier than beating on it with a hammer to get it apart.  You can adjust play in a worn steering box, but should follow the right procedure to make sure you don't tighten it up so much that it binds. 

It probably needs ball joints, but there is quite a bit of work involved in the replacement because the axle shafts and hubs have to come off. You can borrow all the special tools (ball joint removal set) you need from Autozone or Advanced Auto, so most of the investment is in your time.  Thats also a good time to inspect wheel bearings and seals, and to service the front disc brakes.

I would also service both axles and the transfer case (R&R lubricants), and replace the transmission fluid and filter.   Rear brakes may need work, including new shoes and possibly the drums.  Check carefully for leaking wheel cylinders when you have the drums off.

My recommendation is to make a complete parts list and then go to an online store to compare pricing to what you can get locally.  You pay shipping online, and it may be fairly high for heavy parts, but its usually worth it if you are buying multiple parts. 

Bruce

[ehjorten]

Put 500+ pounds in the back of the truck and it will ride just fine! 

I would say you have a couple of serious things you could do that will improve the ride while keeping it stock.  1) You could pull the springs off of the truck, tear them apart, have them blasted, repaint them, put teflon liners in-between each leaf, put them back together, and put them back on the truck!  2) Go to ORD or Alcan and have them make you new springs that are a little more supple.  You will lose a little bit of load carrying capacity, but you could make that up with air bags.

The problem with the stock suspension is that the leaf springs are too short and often times they are all rusted up.  Newer trucks with leaf springs have longer springs.  The deflection in the spring is directly proportional to the length of the spring and inversely proportional to the thickness of the the spring pack.  You can get rid of some friction between the leafs of your stock springs by cleaning them up and putting liners between the leafs.  This lets the spring pack deflect more easily.

[zona98]

Roy, thank you.

Bruce, thank you for the detailed suggestions. I値l start researching everything further. I serviced the axles, transfer case (it still leaks after 3 replacement seals), the transmission fluids, filters and brakes. Replaced all the seals and gaskets and fluids.

Erik, thanks for the feedback.  Replacing springs...any ballpark ideas on how to quantify the improvement? 10% better?  20%?


Any feedback on which shocks to go with? I see opinions across the board. Budget isn稚 determinative, but I don稚 have a need to overspend.

Does airing down tires noticeably help? I知 running 32.5x11 ko2s.  Figure I had them aired up too much.

[ehjorten]

Erik, thanks for the feedback.  Replacing springs...any ballpark ideas on how to quantify the improvement? 10% better?  20%?

That is a really loaded question.  Your stock springs are designed to ride well with a big load in the bed!  If you put a bunch of weight in these trucks and drive them, they ride really nice.  However, if you rarely use your truck this way, it will ride rough.  Places like ORD (they send their specifications to Alcan and Alcan makes the springs), Alcan, Deaver will get you springs custom made for your application and how you use the truck.  How well it rides depends on how good of information you give them.  Giving them accurate weights is a must as well as giving them real information about how much weight you normally carry in the rig.

If I wanted to keep my rig totally stock and wasn't going to put longer springs on it, etc. I would probably start with rebuilding my spring packs.  Over time the ends of the leafs wear into each other and corrosion causes friction.  The use of liners does have an effect on how the spring performs.  Due to interleaf friction all multi-leaf springs suffer what is known as "hysteresis".  That is, it takes more force to start the spring to deflect than it does to keep it deflecting.  The use of either full length liners or tip inserts greatly reduce interleaf friction which in turn reduces hysteresis.  The liners do increase the spring pack thickness a little.  The little tip insert buttons require you to drill a hole in the spring steel at the end of every leaf.  Either method helps to reduce the interleaf friction.

If that method wasn't enough to get me the ride that I wanted, then I would start talking to ORD or Alcan.  I have no experience with Deaver.  If you need to haul occassional loads in your truck, then I would supplement the softer springs with air bags.

[75gmck25]

For the OP - where are you located? 
When I lived in San Antonio there was a local spring shop that would remove and rebuild your old spring set, and you just had to drive the truck in and let them go to work.  However, I don't know where I'd find that kind of shop where I now live.   

Most of the 4x4 spring manufacturers have an option for "soft-ride" springs, but I don't know how much better they are than stock.  I have also seen newer designs that have a lighter spring pack with an overload spring so that you ride on softer springs until it compresses enough to engage the overload and stiffen up.   

I'm still riding on the original 3/4 ton HD springs and camper special package.  My truck does not smooth out until you get about 1000 lbs in the bed, since the springs are designed for a 2650 lb camper load.  However, I've had it loaded well above GVW and it still handled fine.

Bruce

[zona98]

I知 in Phoenix.

This input is very helpful. Thank you. I知 on the search for a shop that might rebuild my springs.

[75gmck25]

It looks like these guys offer what you need.  http://www.valleyspringservice.com/index.php?main_page=page&id=4 

However, based on my experience, you might suffer from sticker shock when you get the price.

Bruce

[roundhouse]

Alcan springs and rancho RS-9000 adjustable shocks make a world of improvement