Looking at a '71 J4600

[AtomicYJ]

I'm looking at a '71 J4600 next week and was wondering what some common areas to check for rust and or known wear parts are? It's got a Buick 350 according to the seller. Its listed as a 4 speed so I assume its a T-18 and has a Dana 20. Pictures appear to show a closed knuckle Dana 44 and seller says semi float Dana 60 in the rear. Scary thing is it has lift blocks up front. Appears to be super straight with mostly surface rust. Hopefully that ends up being accurate. has all glass that appears to be in good condition. Seller says it needs a steering box, should be a Saginaw box and pretty common?. Has a steering column from a Chevy GMT400 truck judging by the steering wheel. How easy is it to find a stock column? Also missing the tailgate which I've read on here is very hard to find. It might be missing some dash components like the gauge cluster. I'm guessing those aren't super common either.

I've always wanted a Buick engined J truck with a 4 speed so I'm hoping this one pans out. I already have a '71 CJ-5 with the Buick 225 and its awesome. Also have some other CJs so not my first Jeep, but potentially first Full Size Jeep.

And on a technical note, besides springs and tires, what are the differences between a J4600 and a J4700? And between a J4700 and J4800 besides brakes, wheel bolt patter, and maybe springs and tires?

Thanks,

Danny

[Stuka]

Welcome to the forum!

That era FSJ used a GM column from the factory, though not a GMT400 as they didn't exist yet. But finding a replacement column should not be hard.

The 44/60-2 setup was used on the mid weight GVW's (There was a full float 60-3 for the highest GVW). Drum brakes forthe 60-2 are a bit hard to find these days. The second number denotes GVW for that era of trucks. So different axles and springs. The J20 got a larger steering box than the J10, not sure if the same was true for the 4000 series trucks.

The steering box is readily available at any auto parts shop.

Tailgates are tough to find. These trucks were not babied, and the single wall center section often meant they were dented up.

Two common rust areas is the bed seams in back. Right along the middle area of the bed sides. The cab corners can also be prone to rust as they can collect water.

[Yeller]

Welcome aboard!

The steering wheel from a t400 will fit the early column too, so it may have the original column in it. About 1990 it was the rage to put a steering wheel from a new truck on your earlier model truck, I did several.

[AtomicYJ]

Thank you both the info, i’ll check the steering column, but it looks just like the one i my daf’s ‘94 K1500. It appears to be a tilt column, was that an option in ‘71?

For the rust area in the bed, is it midline kind of in front of thr wheel wells?

I’ve read up on the brake issue with the 60-2. I’m hoping the drums are still serviceable.

[tgreese]

IIRC '73 was the first year for the GM locking column. Prior to that, it's the earlier non-locking column. I have no confidence that a column from any other vehicle will fit.

The main issue for these mid-weight trucks with the Dana 60-2 (semi-full-floating) is the 12"x2" brakes. The drums have been gone for decades. The front axle can be converted to disks - the Jeep closed knuckle axles are all the same in this respect. Same as the CJ conversion. If you have two good used drums, you could use them on the rears until they wear out. A rear axle disk conversion is also possible.

There is a '62-73 J-series parts book on the Tom Collins site. https://oljeep.com/edge_parts_man.html Suggest you download for reading on your desktop. This will tell you whether the J4800 steering gear is the same as the lower GVWR vehicles, including the Wagoneer. Cores for these HD gears are scarce (large diameter, 4-bolt) - suggest you send your gear to Redhead or wherever for refurbishment if needed. Parts store will likely give you a large diameter 3-bolt in exchange, as an "equivalent."

More likely the PO has clobbered the handling with a hillbilly lift. Blocks on the front are dangerous. Any lift tends to reduce the caster angle, which will make the truck wander. You can adjust the steering gear on the bench following the TSM instructions. AFAIK there is only one aftermarket maker of lift kits for these post-mount trucks, Hell Creek.

Where are you located generally? Jake's wants to clear everything out, in NC.

[tgreese]

JtruckGVWRs.png

This is from the '72 TSM. A '72 J-truck is the same as a '71 except for the engines, and The AMC manual is a lot better than the holdover '71 book from Kaiser. Available on media from RockAuto at nominal cost.

[AtomicYJ]

More great info! I’m in SW WA so NC is a bit too far. I have downloaded that book and was soecifically looking at frames. J4600/4700 trucks w/Buick 350 have the same frame part number, but the J4800 is different. I’ll have to check tue steering boxes, but I wonder if that is why the frames would be different?

I think if I end up buying the truck and tye brakes are bad, i’d look for a set of J4800 axles as I’ve seen it mentioned the 12 1/8 drums are still available

The lift blick scare me, truck is still post mount, and I’m guessing the tires are 35x12.50s. If I end up buying it, I wouod like to run about a 33x10.50 tire. How much lift is required for that?

[tgreese]

I would think none. Likely you have original worn-out front springs. Leaf spring will all go flat after a few decades of use.

The rails are likely the same - might be the post mounts that change. The larger steering gear bolts in for the smaller one; there should be a single bracket listed.

Good luck finding J4800 replacement axles. Scarce, spring-over and closed-knuckle too. Suggest you make it run and drive, then look into axles. The D60-2 used to be popular as material for a narrowed CJ rear axle. Maybe that means disk conversion today, since a CJ owner would have no better luck finding brake parts than a J-truck owner. '74 and newer are open knuckle, sprung under, and called J20s.

[Yeller]

I can verify that no lift is required for a 33x10.50, actually ran 33x12.50's on my J2500 bone stock.

As for the frame differnces, my guess is that it is heavier somewhere with the 8000# gvw.

[tgreese]

If you have two good used drums, you could use them on the rears until they wear out.

An additional comment about this. Usually the maximum oversize for a drum is the nominal diameter (here 12") plus 60 thousandths. That's 12.060". Using a brake lathe, a shop can surface the inside of the drum (turn, grind) to remove any grooves or uneven wear. In the old days, we would also "arc" the replacement shoes to match the new larger interior diameter of the drums.

Last time I worked on drum brakes (the rears of my J20?) my local shop declined to arc the shoes. They said "nobody does that anymore." It can expose the machine operator to dust from the shoes; don't know whether the industry determined it was never needed, or whether they decline to do it because of the potential hazard from the dust.

Ok, say you're in the position of owning one of these trucks with the unobtainium drums. The main issue is the drums. I expect the shoes will continue to be available for the the next decade? Lacking that, you could have your existing shoes relined at one of the places that caters to classic car owners (check the internet or Hemmings). Expensive but not subject to discontinuance.

Any decent automotive machine shop will have the caliper that measures the drum diameter. Can be done on the front counter. Should be no charge to evaluate.

Be very careful buying parts. Aftermarket brake parts listings for these trucks are way more wrong than right.
https://www.rockauto.com/en/moreinfo.ph ... 88&jsn=425

Say you plan to keep the factory axles, want to keep driving the truck, and have drums that cannot be surfaced within factory limits. As above, I would suggest you convert the front axle to disks using the Chevy C10 parts, like a CJ owner would to a closed 25 or 27.

Realize that the rear axle does very little to stop the truck, especially in the case of a pickup, where nearly all the weight transfers to the front axle when stopping. With drum brakes, you typically get twice the life out of the rears as the front, maybe more.

Following is just advice. No guarantee of suitability for your situation implied.

You may be able to put the rear axle together using the drums you have, and don't surface them. This will do a couple of things; first, the new shoes won't be very effective until they seat into the uneven drums. On the rear axle, we probably don't care about this. Next, the shoes won't last as long because part of the material will be (comparatively) quickly worn away by the uneven drum surface. Maybe not acceptable for a daily driver, but ok for a hobby / occasional truck.

You could also turn the drums larger than the factory spec. I suspect the main problem with this is the expected travel of the self-adjusters. It may also be difficult to find a shop that will turn drums beyond the factory spec, due to liability concerns. I know from experience (auto shop days) that this can work ok. However, it's likely safer to accept the uneven drums and extra shoe wear, especially when used on the rear axle. If I took this approach, I'd require using/conversion to a modern dual-circuit master cylinder.

[AtomicYJ]

Looked at the truck this morning. Overall I think its in good enough shape, and has a title. Motor turns over, won't stay running. Seller thinks its the carb. 2bbl Buick 350, shouldn't be hard to rebuild or get a new Rochester 2G.

Transmission shifts through all gears, transfer case has no positive engagement through the shifter, but its connected and the rods move. Clutch is free.

Shaft on the steering box is stripped out, looks to be a standard Saginaw 3 bolt box. Column looks like an early GM tilt/locking unit, but it appears to fit the truck well. Gauge cluster is missing unfortunately.

Lots of surface rust, there's a good 4x6 chunk of the bed floor missing on the passenger side up near the cab. A few spots in the seam in front of the wheel on the drivers side. Cab corners and solid as is the cab floor. There's a part of the outer panel on the cab roof that looks like it got torn on something. Inner panel under neath still seems solid. I'm sure there will be more once that is dug into. No major body damage. Box full of random trim, no exterior badges though.

Frame is super clean, very minimal flash rust on the rearmost crossmember, didn't see any crack or bends.

The trim tag is missing, and I couldn't decide what color it was. The pictures of the dash made it look very blue, but its teal in person, so I'm thinking Spruce Tip Green originally. Love that color. No seat, but the sun visors and door panels are somewhat there and are teal-ish as well. Yellow build date sticker is mostly worn away and is unreadable.

Told the guy I'd take it once he gets the title from the DOL. He apparently bought it from a member of the family that bought it new, and other than the janky lift blocks, tilt column, and wheels and tires, its fairly original.

[tgreese]

We like pics.

[AtomicYJ]

Ask and you shall receive

[Yeller]

Definitely needs some love but looks doable

[devildog80]

Oh yes.....diamond in the rough just waiting to be polished. You have 100% more there to start with then some we have seen.
Following

[tgreese]

Plenty there. All solid, desirable drivetrain. I would a) look for a factory column, and b) media blast. Lots of these trucks survive in the PacNW, it seems. Don't lose those bumpers, esp. the rear.

Looks like somebody started to strip the original paint, and covered in spray can primer. That gray primer is not very weather-proof.

[AtomicYJ]

It has about 20 times less rust that my ‘71 CJ-5 had when I bought it, but its also a Renegade II. Super excited. Love the Buick motors and manual transmissions. There’s an old style GM power steering pump in the cab, how hard are the brackets to find for the Buick V8? And are the rear bumpers hard to find like tailgates?

I intend to put a stock column and wheel in it. Nice thing is once I pick it up it will be under cover until I can get cranking on it.

And it turns out my brother in law has 2 good/new drums for the brakes he took off a 60-2 for his race jeep.

[tgreese]

Obvious power steering donors would be '68-70 Wagoneers (nearly all Wagoneers have PS/PB), or passenger cars. I would expect that all the Buicks in this family 225/300/340/350 would have compatible brackets and pulleys when running power steering. Big block Buick parts from the same era may work too - IIRC these engines nearly drop in to replace the 350. The V6 CJ guys (factory and converted to the 225) have been scavenging these parts for their 225s for a long time. I recall this setup has a high and a low mount version; your truck has more room under the hood than a CJ. Could maybe search or ask on earlycj5.com.

Looking on car-part.com, I found seven engine donors for a 350 Wagoneer in the NW. Commercial yards are not the cheapest source, but otherwise a good option.

Also Jeep did not go to the year-by-year type of VIN until 1972. Prior to that, the VIN numbers were assigned sequentially, and there was no obvious year designation in the VIN. I presume the production year was assigned by the dealership at time of sale, when they processed the new title. Officially, a '71 should have an AMC V8 (304 or 360), not a Buick, even though there are putative '71s out there equipped with the Buick. Jeep owned the 225, but presumably they bought the 350 as a commodity engine from GM/Buick... possibly they had stock into 1971 or a commitment to buy or something. May be important when you buy parts.

Good news about the drums. Very lucky. Would be interesting to know how many good examples of those drums still exist ... very few I'd suppose. You'd need some kind of omniscience to find them. Maybe if you offered a big enough reward and publicized it widely, you'd find all that are left.

[tgreese]

No mistaking those valve covers!

I'd have to check the parts book about what crosses over from Wagoneer on the front bumper. I expect the center section of the J-truck is longer.** Most Wagoneers have chrome bumpers. Bespoke step bumpers are hard to come by; this truck is narrow compared to Fords and Chevys. The wide flares and rear axle were used so there could be more than 4' between the rear wheel wells. 4x8 plywood etc. lays flat.

** Nope, same for the Wagoneer. Apparently they just mount the ends out further and expose more of the center section on a J-truck.

[candymancan]

Maybe its just me.. you all know i did extensive repairs on my J10.. but id stay away from that one.. rebuilding a bed and floors like i did is easy amd cheap compared to finding all the parts that thing needs.. but thats just me.. Mine had a boat load of rust which the majority ive cut out and repaired.

But mine had the entire interior and bumpers and everything.. Its why i got it despite the rust. I dunno thats just me of course. Im diff when it comes to things like that i guess.