Carrier Bearing Position

Driveline needs to be straight thats the correct position.

 

Driveshafts are not straight. They have to bend to accommodate the axle moving up and down and maybe a little side to side as well.

In any case, if our goal is to make it straight as possible, I think we should be offering ideas on how to measure its straightness rather than assuming the original position makes it straight.

 

TBQH, I think when I installed my spacer, I loosened one bolt at a time without removing either, but only because it was dark and I didn’t want to deal with trying to thread the bolt into a hole I could not see.

There’s nothing about that bracket that cries out precision. On the contrary I think it is designed to allow deviation/slop/tolerance in the rest of the assembly. I.e. it’s not the source of truth.

 

If his carrier bearing was in that position when he removed both bolts and did nothing else.
It should go back to that same position.

 

You are assuming two things: 1) there is a correct position and 2) it was in the correct position previously.

 

if he wants to maintain his initial vibration problem

 

One thing that is important about drive shafts is that the non-constant revolution speed of u-joints is properly compensated for. The details are dependent on the design of the driveshaft, but generally are focused on matching the angle of the u-joint at one end of the drive shaft with the angle of the u-joint on the other end. If this is not done correctly, it leads to vibration. The carrier bearing bracket is not involved in this, except for holding a spacer in place. You can determine the correct angles using a digital level. There are some videos on youtube.

 

My money is on something else is causing his vibes.
Not where his cb is.

 

Not looking for a lecture on driveshafts but thanks.

I'm not assuming anything. It came off in one spot so it should go back in that same spot.....
He didn't do anything to change that.
Do you understand?

 

No I don't understand. I have no reason to believe that the carrier bearing bracket needs to be in any particular position to a degree of great precision. I think it's designed to allow the rest of the assembly to determine the correct position. I feel like we are talking past each other.

 

He can barely get the bolts back in.
This isn't about 'correct' position.
It's about being able to get the mofo back on without getting a hernia.
Idk how else to explain it so I'm going to wait and see if he can get it to slip ahead a little more.

 

Huh? That's how I understand his post. His picture shows them back in. He seems to be worried about them not being back in the same position as before.

The driveshaft alignment post was not directed at you specifically and it was in response to my thought thst people might be distracted by carrier bearing bracket positions when they should be thinking about driveshaft angles.

 

Read.

 

that is most likely true but the positioning of the CB will affect driveline angles, and as i remember, there are pretty tight tolerances ie a degree or two, in the specs. it would make sense that keeping the necessity for universal angle correction to a minimum would be a goal in the driveline, but static loading is not the only story...axle wrap accelerating or decelerating will figure into the angle specs.
i was being facetious when saying if he wants to maintain vibes, but there is truth to starting from ground zero and investigating responsibly from there.
with a lift though, it will be hit or miss. i don't recall any specs talking about lifts. driveline angles toyota cares about is for unlifted.

 

Another thought it is that the assembly has gone through multiple hot/cold cycles, mechanical wear, etc. since installed at the factory. It's quite likely that things have shifted such that the "correct" position of the carrier bearing bracket has changed.

 

I'm picturing a NASA engineer in a climate controlled room at the Toyota factory adjusting the carrier bearing bracket (and the body panels) to .01 microns of precision using the latest laser alignment tools.

 

As long as the carrier bearing was installed correctly, there isn't much you can do about it. Just like @BLtheP said. FWIW the manual actually shows it maxing out the slots.

 

Audi quattro and VW syncro cars (and BMWs) from the 80s-90s have a two-piece prop shaft with senter carrier bearing for their AWD systems and take a very special tool to keep the shafts straight.

Does Toyota have anything like them?

 

Doubtful. On a stock truck, I have tested it. My driveshaft is happy at very high rpm with the carrier bearing as far left or right as it will go on the bolts. As discussed, you can’t change the fore or aft position due to the front half being fixed and bolting to the tcase flange.

Lifted trucks may be more fussy due to the extra added angle, but Toyota wouldn’t have a tool for that I don’t think. Especially since lift kits like the TRD don’t even reference doing anything to the driveshaft at all.

 

No. Toyota generally doesn't make things overly complicated, unlike Germany.