HI GUYS.
Undergoing a SAS swap. Was looking and doing research and wondering why everyone (mostly) uses the cut a hole in the frame and weld in a tube route instead of using these on the front end for the rear of the spring? is it because it will throw off the pinion angle too bad?

 

pretty much.
i have seen it done but your pinion looks fubar, it has worked on Taco SAS though

 

I mean would it throw it off that bad? Putting and angle shim under the spring pack wouldn't fix it? i guess you could also cut off the spring perches and rotate them ass needed, but that would probably be more work than doing the hanger mount the regular way.

 

Pinion angle isn't the only geometry you need to worry about, caster angle is also important, if it's negative your truck won't go straight if you let go of the wheel, it'll turn on it's own. if it's too much it makes it harder to steer. Just be very aware of the whole picture if you do plan to start rolling your pinion and axle around.

 

AKwheeler has a good point
the only real way to correct pinion angle that gets fubarred like that is to cut and rotate the knuckle balls.
Toyota built the 79-85's with the rear mount through the frame for a reason and why 99.5% of SAS conversions on 86-95.5 trucks are done a similar way

 

Ok makes sense. i just figured what ever degree amount the pinion was off i could simply correct it with angled shims under the springs. also thought if the pinion and the t-case output shaft angles matched then the caster would be ok. guessing its not that simple?

 

I'm not sure, but I suspect that the shackle mounts are buried in the frame due to the front end side load. when cornering there is far more sideways force than on the rear and with the mount below the frame there may not be enough structural rigidity. Just my thought, I don't have anything to back it up other than what I have heard about lift blocks, nobody recommends that you use them on the front suspension, but they are common for a rear lift kit. for that same reason I wouldn't suggest using shims on the front to angle your pinion.

 

good point. ill just order the jig and tubes for the front.