Messed up my Rear Bearing press - can speed sensors be installed in front?

I ordered left and right rear bearings from Rock Auto and had a mechanic install them on my axels for me. Problem is, he oriented the speed sensor holes toward the front on BOTH SIDES.

(pictures below)

On the driver side, I believe the speed sensor is supposed to be installed in front of the axel (is that correct?)

But on the right side, the speed sensor is supposed to be installed behind the axel.

Question: Can I fix this easily by just extending the speed sensor cable on the passenger side and install it in the front of the axel instead of in the rear of the axel as it came from the factory?

Or would that confuse the computer? Is the speed sensor oriented? Does it just read pulses or does it also read direction of rotation?

So I believe what actually caused this whole problem is this: I think Rock Auto sent me TWO driver side bearings. You can see from the pictures below that the sensor holes are oriented exactly alike on both assemblies.

I didn't notice this. And neither did the mechanic. The mechanic just pressed them both on without inquiring about their proper orientation.

My first mistake was: I did not carefully check the parts that Rock Auto sent me.

My second mistake was: I did not take before pictures to give to the mechanic and to assist in the re-assembly.

My quandry is, it would be a serious hardship for me to buy a new bearing and have the mechanic do another removal and press (he charged me 2 hours, $350 per side). Having hit 125k on my Taco, I've been suffering a lot of part failures lately and after thousands of dollars of work I am not in good shape. I'm bleeding cash by renting a car. I'm straining my friend's hospitality while my truck takes up his garage. I would like to get these axels installed immediately with minimal expense.

Is there a way that I can just run with TWO driver side bearings? I think the only difference is the speed sensor holes.

I am concerned that if the speed sensors are oriented (they can tell forward speed from reverse speed), then I need to be careful to get the orientation right if I'm going to move the sensor from the back to the front. Not sure what the computer would do if it thinks the wheel is reversing when it's really moving forward. So I need a careful understanding of how that sensor works.

In the images below, note that the speed sensor bolt hole (threaded) is on the same side of the sensor socket on both bearings. I believe these are both Left Side (Driver Side) bearings.

Images:

Passenger Side Assembly (MISTAKEN INSTALL) (I believe this is a Left Side bearing installed on the Right Side axel)



Driver's Side Assembly (CORRECT INSTALL) (below)

 

Personally I’d make the shop redo it correctly and pay for any parts that are not reusable.

 

This - you paid for a service. If they did it incorrectly, it should be on their dime and time to fix things - not your dime and time. Mark the parts in some permanent way so you can identify if they reused parts that should not have been reused.

The speed sensors operate on VERY low voltage differentials at very low amps, so are very susceptible to signal interference. I don't know if it's possible extend the cable (or add an extension) without causing problems with the signal. I assume it's possible if shielded cabling is used.

But why bother - tell them to redo it bottom line and save yourself the grief of trying to kludge their f-up.

 

I agree with you, but because I supplied the parts, I

I would like to do that, but I am expecting that they will argue that the fault is mine because I handed them a wrong part.

They should have known better, and should have warned me before installing, but I'm expecting them to not be impressed by that line of reasoning.

 

Hogwash. When they removed the axles they should have made note of the orientation of the bearing assembly in relation to each side and the brake backing plate. This is 100% on the shop.

 

X2! Emphasis on the HOGWASH!

 

I need some ammo to approach the mechanic … Does anyone have photos or factory manual diagrams showing the orientation of the speed sensors on both sides?

 

1st pic is Right Rear. The sensor is opposite of the entry of the e-brake cable. On the left it’s on the same side as the e-brake cable. So right rear it’s on the back side of the axle on the left it’s on the front side. Hope this helps.

 

You DIDN'T give them the wrong part (I assume), so they can't use that argument. You gave them the RIGHT part and they put it in the WRONG WAY.

 

I gave them two left side bearings.

(Rock Auto sent me two lefts when I had ordered a left and a right. I didn’t notice the problem before handing them over to the mechanic).

 

Ah, bad on me for not looking/reading carefully. No ammo - except that that's a pricey fee for labor. It took me (diy) about an hour for BOTH sides, and it was the first time I did a Taco.

I don't think any shop will give anything if you gave them the wrong part.

I checked the FSM I have, and unfortunately, there is no explanation or image other than to state to be careful because the two sides are different.

If you live in NH, I can offer the use of my bearing tool and press.

If it was a matter of the wrong side bearing being pressed in the correct orientation, I have read that some have successfully drilled and tapped a bolt hole on the correct side, but that doesn't seem to be your case.

 

So then one is on correct and one isn’t?

 

I'm getting that one side (driver's) is the correct right bearing, installed in the correct orientation.

The passenger's side is not only the wrong bearing, but also installed in the wrong orientation (double whammy). If it was the wrong bearing but installed in the correct direction, I THINK some have drilled and tapped a new bolt hole on the other side of the sensor hole.

 

A possibility is if you can purchase the correct mating connector from somewhere like Ballenger, you might be able to buy a standard replacement wire, cut the sensor side off, and replace it with the mating connector to make an "extension cord." But like I said earlier, I'm not sure if it would work because of signal is so low and prone to interference.

Another thing to consider - I don't know if it's the case on the rear of the Taco - the mag strip on the bearing MIGHT be directional (so the system knows if the wheel is spinning in forward or reverse), so even if the above might have worked, it won't work because the bearing would be spinning in the wrong direction.

Edit: I should mention that a lot of connectors on Toyotas are Sumitomo.

 

Thanks for raising this point!

I was also thinking of having them rotate the bearing around to orient the sensor socket to the rear and then having a machine shop drill out a new bolt hole to mount the speed sensor. But if your guess here is right, that sensor would read reverse speed on the right wheel while the truck is moving forward.

 

That would be such an easy way to fix it if the sensor would work right on a wrong side bearing. If you have any links to share of a successful fix like this, I'd like to see it.

 

If this idea works, I'd like to see some links to such stories.

I may be able to convince the mechanic to correct the problem by remounting the bearing 180. Then I could have a machine shop drill a new mounting bolt hole.

But if the mag strip inside is different on the two bearings, that might cause problems for the computer because it might read reverse speed on the right side bearing because it is really a left side bearing?

 

Actually, it seems that this idea WILL NOT work. Found this quote in another thread:

Also in that thread is a reference to another account where bearings were installed on wrong sides and the speed sensors generated faults on the freeway for speeds over 100kph in reverse.

Sigh.

So now I gotta throw out a brand new Timken bearing and buy another one.

 

I accidentally flip flopped my bearings. The tone rings are indeed directional. In the wrong orientation I would run up to 60mph and the Speedo would drop to zero. I rotated them and drilled a hole to put the mounted stud on the opposite side and it works fine to this day

 

Interesting. What do you mean you "rotated them"?

Did you rotate the backing plate 180 degrees so the sensor mounting holes were on the correct sides?

That still would leave you with mag strips rotating in the reverse directions.

In this article the guy diagnosed wrong side bearings by noticing that the mag strips were generating reverse speed pulses while rolling forward and vise versa. This implies that the directionalness is more than just the mounting holes but is in the magnetic ring itself. If that is true then leaving a left side bearing on the right side could really mess with traction control, etc. I would fear damage to the differential if any of the wheel control programs were activated by the computer because the computer would be confused about what direction the wheels were spinning.