Okay I'll try to keep this brief.

About my truck, 400/C6/NP205...factory 9" & Dana 44 with 3.50's.
The only real modification worth noting, 35x12.50 MTR's.

The truck is not a daily driver, gets driven around the neighborhood about once a week, 2-5 miles.

I have two issues that I'm trying to diagnose/fix.

Isssue #1: It seems as if the four wheel drive system is locked into 4x4 and won't disengage.

The NP205 has the correct fluid level, the front hub selectors on each side move freely between LOCK/FREE. The NP205 shifts smoothly from 4L, N, 2H, 4H not binding up...but the front driveshaft will not spin freely, by hand when the transfer case is locked in 2H.

From previous attempts to diagnose, if the front hubs are unlocked and I put the truck in 4L I can feel the front end pull like a tractor.

Am I correct in thinking that if the 4x4 system is "unlocked/free" that I should be able to spin the front driveshaft by hand?


Issue #2: It seems like after driving for a short while (2-5 mi) that the front passengers side brake caliper is hung up. The wheel gets very hot and smells of hot brake pads.

Could this be just a stuck piston in the caliper? Could it be something as simple as surface rust built up restricting the piston movement?

I had the entire brake system rebuilt less than 500 miles ago, using the best quality/heaviest duty parts that I could buy. Everything was installed correctly by a competent mechanic, no issues driving the truck after the brake job....util now.

I may need to start driving this truck soon as my daily driver and I'd like to get these issues resolved asap.


If you guys could help me diagnose these issues I'd be eternally grateful as my budget is kind of tight right now.

Thanks for reading.

 

Going by what you have stated....here ya go!
Issue # 1. Sound like the shifting fork for 2WD to 4WD might be worn. It is possibly the fork or the shaft it is mounted to. If I remember right, it is mounted to a shaft with a roll pin. Sometimes the fork gets "hogged" out a little from moving 2WD to 4WD. Not too hard to do. Check the transfer case shifter linkage too!!
Issue # 2. Definitely sounds like a caliper hanging up. If you had brakes done with calipers...take it back to the shop where you had them done. If you just had a brake job done, you'll need to get a new or rebuilt caliper....preferably do BOTH calipers. If the rotor is burnt "blue", get it turned or replace it as well and it probably wouldn't hurt to repack the bearings on the hub that was getting hot. Hope this helps!!

 

Sounds like you need to service your hubs. Too much grease in them gums them up and they don't like to release.

Also, you have a hung brake caliper. Sometimes backing up will release it. Have a mechanic figure out why it hangs.

 

Sorry Matt, I didn't see this until it was too late.

 

Matt, rogue..thanks for the input.

Yes the brakes were completely rebuilt, new HD rotors/calipers/pads on the front...new drums and internals on the rears. IIRC, the front wheel bearings and manual hubs were treated to a fresh greasin'.

I probably should take the hubs apart at a minimum and see what the grease/lube situation looks like inside. I guess it could be something as simple as that....the 4x4 system on this truck has always worked flawlessly before...kind of strange for it to be acting up now, especially since the last time that I had it locked in was two years ago for some heavy snowfall that we had up here.

I know that it's bad for cars/trucks to sit un used, seals leak, tires get flat spots, etc. that's why I try to take this old girl out for a weekly spin.
I guess that these problems would be easier to rationalize/explain through hard use of the truck.

 

No problem!! It's all good!

Blackjack, check and make sure you don't have a kinked/damaged metal brake line. Also check the brake hose on the caliper hanging up....they can swell inside and act like a "one way valve". Especially older hoses and trucks from up north!

 

If you wind up replacing the calipers (again), it'd be a great time to buy a set from a 79 T-bird and install those instead of the truck calipers.

Here's a link about it.

 

Matt, good ideas...I'll check them out.

psychlopath, I was looking at doing the F350 upgrade to the Bronco but I couldn't get all the needed parts quick enough for my mechanic's schedule. I have a brand new set of F350 wheel cylinders, etc in parts storage.

 

If you wind up wanting to upgrade later, it's my suggestion to scrap the 350 stuff and just go hydroboost. I never could get that 350 stuff to work worth a darn...but I seem to have poor luck with it all.

I finally went hydroboost and never looked back...it's been two years and I STILL smile when I hit the stoppers.

 

hrmm...

ok so I took the hub covers off of both sides of the front axle, inspected them.
There was plenty of good grease in both, manually worked the action of both, seemed to work as intended, cleaned up the outsides a bit and put them back together.

Checked the front brake lines/hoses from the MC to the proportioning valve..everything looks to be good...a bit dirty with some surface rust, but no damage.

Too much grease in the hubs?

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dirty transfer case linkage

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Did you have the Rubber lines going to the caliper replaced? When they get old they can collapse internally and cause the caliper to hang up. This happened to me on my 88'. $15 for a new hose and I was on my way again.

 

Yep, they're new. The only thing on the front brakes that didn't get replaced was the aluminum block that runs across the axle and the little "T" block.

I think that I"ll pull the hubs apart this weekend and double check that things are engaging/dis-engaging as they're supposed to.

If I have to replace a lock-out hub...what's the preferred brand/type...Warn premiums or Mile Markers?

Thanks!

 

Hey man, you have way to much grease in those hubs. You only need to apply enough grease to semi-coat everything. Use a Q-tip to apply lightly. As for replacing the lockouts, I would try to buy a set of original factory spicers (best-imo). Thats what I have on all my 79 bronco's & truck's. I guess some will tell you to buy warn's and they are ok but not as good as the factory original spicers--just my .02

As for upgrading your brakes, I did the F350 upgrade on (3) of my bronco's and love them, with using t-bird calipiers--no problems and stop on a dime at 65mph on 35's. But, psychlopath is correct the hydroboost is the best way to go in the long run!!

 

Thanks Scott...I'll get them torn down and cleaned up/degreased this weekend.

Hopefully that'll solve one issue.

Thanks to everyone who's helped!!

 

Yeah scott79 hit the nail on the head.