Common 3B Issues

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S

spectre6000

10 Year
Joined
Dec 22, 2011
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Location
Coal Creek Canyon, CO
I'm hoping to buy an '81-'84 BJ40/42 in the near future (as soon as I sell my VW Bus), and I know what to look for in terms of metal work (rust, filler, and new paint being negatives) and can identify general mechanical issues as they apply to every automobile, but I'm not as familiar with the mechanical issues that are common to 3Bs.

What are common mechanical issues? I.e., weak connecting rods, always carry a spare fuel pump, etc.

What parts/systems are prone to frequent significant wear? I.e. rings, bearings, etc.

Finally what are some of the more common expensive repairs? I.e. any of the above that are expensive particularly time consuming to fix.

Thanks.
 
Nothing really goes wrong consistently in a 3B. Virtually any 3B is good for 300km, even with some neglect. After that age sets in but there isn't one thing that consistently kills them.

... but there are some "random" failures that strike.

The weakest link is the precups, which do occasionally crack and fall out onto the cylinders. Cracks in precups are a sure thing; they are always cracked. Cracks bad enough to cause fracture are open for debate; an extreme overheating event or running a turbo on high boost are correlated with the droppage, but not always. I doubt you could even tell by looking if the cracks are serious or not, so its is standard practice to replace them any time the head is off.

Some of us have found that cam bearings can go bad and cause marginal oil pressure. Mains and rod bearings seemingly never do.

Oil pumps seem to be bulletproof, though they're so difficult to replace that there aren't many people here who have chimed in to say "I replaced my pump and it fixed X" or "Y."

Alternators have a vacuum pump on the back for powering the brake booster. Sometimes the pump splines can strip. No idea what causes that, but its not "common."

Primer pumps are notorious for leaking - that can mean they let air into the system and cause stalling, or it can mean they don't work very well. There is a Bosch replacement listed in the sticky that will last forever.

I think thats about it, really. 3B's are quite tough.

The rest of the draintrain has some things to look for...

Seals between the transmission and Tcase go bad, causing oil to move from one to the other. Fixed with a bypass hose, or a teardown to get at the internal seal.

Birfields are a weak link for sure if you have big tires and a heavy foot (maybe not such a big deal with a 3B as if you had a 350 swap).

Pinion and TCase output nuts loosen and or the shim packs wear down, causing looseness in the DS yokes. If not caught in time it can make lunchmeat out of the differential. Checking for radial play is all thats required, if any, retorque the nut (slightly controversial, this might result in high preload if your shim pack is dead................ but it works).
 
Good summary right there Drew!


amaurer said:
Nothing really goes wrong consistently in a 3B. Virtually any 3B is good for 300km, even with some neglect. After that age sets in but there isn't one thing that consistently kills them.

... but there are some "random" failures that strike.

The weakest link is the precups, which do occasionally crack and fall out onto the cylinders. Cracks in precups are a sure thing; they are always cracked. Cracks bad enough to cause fracture are open for debate; an extreme overheating event or running a turbo on high boost are correlated with the droppage, but not always. I doubt you could even tell by looking if the cracks are serious or not, so its is standard practice to replace them any time the head is off.

Some of us have found that cam bearings can go bad and cause marginal oil pressure. Mains and rod bearings seemingly never do.

Oil pumps seem to be bulletproof, though they're so difficult to replace that there aren't many people here who have chimed in to say "I replaced my pump and it fixed X" or "Y."

Alternators have a vacuum pump on the back for powering the brake booster. Sometimes the pump splines can strip. No idea what causes that, but its not "common."

Primer pumps are notorious for leaking - that can mean they let air into the system and cause stalling, or it can mean they don't work very well. There is a Bosch replacement listed in the sticky that will last forever.

I think thats about it, really. 3B's are quite tough.

The rest of the draintrain has some things to look for...

Seals between the transmission and Tcase go bad, causing oil to move from one to the other. Fixed with a bypass hose, or a teardown to get at the internal seal.

Birfields are a weak link for sure if you have big tires and a heavy foot (maybe not such a big deal with a 3B as if you had a 350 swap).

Pinion and TCase output nuts loosen and or the shim packs wear down, causing looseness in the DS yokes. If not caught in time it can make lunchmeat out of the differential. Checking for radial play is all thats required, if any, retorque the nut (slightly controversial, this might result in high preload if your shim pack is dead................ but it works).
Click to expand...
 
If you buy an old 3B do take the head off and change the pre-cups. Its dead simple and none of the above mentioned will competely destroy your engine like a pre up dropping 4 quarters worth of metal into your cylinder. That being said, they are good for quite a while when done. I change mine now like you would a timing belt.
 
gerg said:
If you buy an old 3B do take the head off and change the pre-cups. Its dead simple and none of the above mentioned will competely destroy your engine like a pre up dropping 4 quarters worth of metal into your cylinder. That being said, they are good for quite a while when done. I change mine now like you would a timing belt.
Click to expand...

Do you replace your head gasket, and what do you pay for it when you do?
 
hmmm has me wondering if I should take my head off and replace them while I have it partially torn down. Where do you source them from?
 
Yes, replace the head gasket whenever the head comes off.

Use the latest p/n OEM gasket. The latest OEM gaskets are MLS construction and superior to the composite gaskets used previously. All aftermarket gaskets I'm aware of are composite.

(That said, the composite gaskets in 3Bs aren't a weakness. I've just had better luck with MLS personally, and think they are technically superior. I did have one cheapy aftermarket head gasket fail in a matter of months, but I can't tell you if that was my fault or the gasket's.)
 
Would the dealer carry the headgasket/pre-cup set or you go to the usual vendors?

SOR, 4WheelAuto?



amaurer said:
Yes, replace the head gasket whenever the head comes off.

Use the latest p/n OEM gasket. The latest OEM gaskets are MLS construction and superior to the composite gaskets used previously. All aftermarket gaskets I'm aware of are composite.

(That said, the composite gaskets in 3Bs aren't a weakness. I've just had better luck with MLS personally, and think they are technically superior. I did have one cheapy aftermarket head gasket fail in a matter of months, but I can't tell you if that was my fault or the gasket's.)
Click to expand...
 
11115-58110 is the HG, which my usual sources say might not be available. 11115-58080 might work also, which was the number for 3B's after 1988. If your dealer can't find it it doesn't necessarily mean you can't get it, it just means you need a more uber dealer. Some of our vendors on this site have an uncanny ability to get "discontinued" parts from Mr. Toyota.

Precups I've never heard of coming from the dealer, but I doubt you'd want to - they were $200 ea. or something. Get aftermarket.

4wheelauto is a good bet for both. I got my own OEM HG there.
 
Thanks Drew!

-Alberto

amaurer said:
11115-58110 is the HG, which my usual sources say might not be available. 11115-58080 might work also, which was the number for 3B's after 1988. If your dealer can't find it it doesn't necessarily mean you can't get it, it just means you need a more uber dealer. Some of our vendors on this site have an uncanny ability to get "discontinued" parts from Mr. Toyota.

Precups I've never heard of coming from the dealer, but I doubt you'd want to - they were $200 ea. or something. Get aftermarket.

4wheelauto is a good bet for both. I got my own OEM HG there.
Click to expand...
 
MLS Head gasket from toyota is like 150 bones... cheap. I get my pre cups from roodogs on ebay. 130 bucks shipped to my door for 4 stainless ones. All in all hardly out of anyones price range. However, most people dont do it until its too late, then they complain IDI engines are s***e, when they just need a little regular love like any other vehicle.
 
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Dbradford04 said:
hmmm has me wondering if I should take my head off and replace them while I have it partially torn down. Where do you source them from?
Click to expand...

Just replaced mine got head gaskets and cups from www.cruiserparrts.net good price and great service that have ALOT of 3B parts too
 
Other then the crank case cover gasket that often leaks, if the motor do not over heat it will run for a looonnng time. When they fail, often it is the combustion precup that falls in the cylinder.

Seriously the engine is not a concern at all compared to the body (aka rust).
 
Pecups

The link should take you to a thread I started some time ago when I had precup (stainless aftermarket) failure at about 150K Kms. The precups that were still in place did not show the degree of cracking that I have seen on the OEM cups. I won't repeat what is in the thread but I still am at a loss as to the reason for the failure. I used the same stainless cups from 4Wheel Auto in a freshening up of the 3B I got to replace the "pooched" engine in the photos.

https://forum.ih8mud.com/diesel-tech-24-volts-systems/404764-3b-engine-issue-suggestions.html


jzilla said:
Greg how do the stainless precups look after you have run them for a while? Any cracks?
Click to expand...
 
The HG on the pooched engine looked like material had been cut out exactly around the precup, or is that an illusion? I have had old heads with all the precups cracked and wiggling around and some you could remove by hand. It takes alot to actually crack them into pieces. Failures such as yours are why have chosen to change them at around 150ks. A bore scope would be nice to cus you could just poke it in the glow/ injector hole and directly look at the cup and inspect it for cracks.
 
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