UCA replacement

Hi guys. Been lurking a long time but figured it was time to join. Does anyone know why UCA axle bolts are facing down and to the rear of the vehicle? Wouldn’t it be easier to remove them if they were in the other way? Am I just dumb or doesn’t it make sense to reinstall the same bolt backwards so it’s easier to get it out the next time?

 

They are installed that way to reduce the chance of the bolt backing out if the nut were to fall off. Although I’ve personally seen this happen on two separate vehicles and the bolts still backs out partially. There are plenty of people that reinstall the bolt backward (uphill) and never had an issue so it’s up to you if you want to take that chance.

 

Yes, Toyota's prototyping shop also installs the bolt pointing forward. See 2022 TRD Pro press photo:



Production models have the bolt pointing rearward again. My photo at my local club meet:



Toyota likely did it this way to ease installation during production - workers can have the UCA hanging with just the bolt inserted while they turn around to get the nut from the bin. The entire suspension (UCA, LCA, shocks) is installed onto the frame, possibly on a different line, before the body is dropped onto the frame.

Being a rotating joint with the bolt in single-shear, the nut has a tendency to loosen, particularly if you do a lot of dirt roads. Mine came loose twice, so I now use

$14 uxcell 4pcs M14 x 1.5mm Pitch Metric Fine Thread 304 Stainless Steel Hex Lock Nuts

M14x1.5 stainless nyloc nuts there, though it requires a larger 22mm or 7/8" wrench to tighten.

 

Ohh okay that’s smart. I just did mine backwards because I’m lazy but locking nuts are a good idea. I drive like 50 miles a day on a very washboardy dirt road so thanks so much for the heads up.

 

or you can use a jam nut as well.
and thread locker for added security.

 

It's just assembly as mentioned. Lots are installed backwards no issue. Just retorque a day after driving and it's good.