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Anyone report on net change to front caster with lowering rear end. I would think it would have favorable consequence (increase +) just not sure how much change expected. If enough to deter DW i would consider.
I had to re-center my steering wheel after lowering the rear end. -Mike
That should not be necessary. Did you use aftermarket blocks having multiple holes for the locating pin? If so, it sounds like your pins are not in the same holes of the new blocks, and your rear axle may now be out of square with the truck's centerline. It happened before with another poster further back in this thread. You can check this by measuring from your axle tube to the center of the bolt which holds the leaf spring in the forward perch on each side. If the left and right measurements are not the same, then your axle is out of square.
Anyone report on net change to front caster with lowering rear end. I would think it would have favorable consequence (increase +) just not sure how much change expected. If enough to deter DW i would consider.
Lowering 1-1/2" in the rear will add 0.54° positive caster on a CCSB and 0.49° on a CCLB.
Lowering 1-1/2" in the rear will add 0.54° positive caster on a CCSB and 0.49° on a CCLB.
What will the change in caster cause? Can it be adjusted back to spec with a front end alignment?
I plan to lower mine using Ford parts and after all the travels this summer and now with 30,000 miles on the truck my steering wheel seems a bit off center and the truck seems to more sensitive to the crown in roads (with and without 5th wheel) than I remember when it had fewer miles. So I was going to get the alignment checked anyway. Maybe that should wait until after I lower the rear end.
What will the change in caster cause? Can it be adjusted back to spec with a front end alignment?
I plan to lower mine using Ford parts and after all the travels this summer and now with 30,000 miles on the truck my steering wheel seems a bit off center and the truck seems to more sensitive to the crown in roads (with and without 5th wheel) than I remember when it had fewer miles. So I was going to get the alignment checked anyway. Maybe that should wait until after I lower the rear end.
Originally Posted by V10DoubleTow
Lowering 1-1/2" in the rear will add 0.54° positive caster on a CCSB and 0.49° on a CCLB.
Prior to lowering my truck both I and the wife noticed the increase in steering and trucks "bumpiness" and overall handling as compared to our 03 F350 DRW and granted while they are much different trucks the difference was dramatic. I was not too surprised by the increase in "truck" feel moving from the DRW to the SRW.
That said after lowering of the rear the noticed "lack of smoothness" was drastically reduced, in fact the wife asked if I changed the shocks or anything else so IMO and based on observation I know the overall handling of my truck improved with the change in height and resulting change in caster. Additionally I can now access the bed which is 2 inches lower at the tailgate and the horse trailer rides at a better angle due to the drop in height.
So a WIN-WIN -WIN for us!!
And for those that have the steering wheel off center issue, I had/have no issues with the steering wheel being off center before or after lowering the rear.
Lowering 1-1/2" in the rear will add 0.54° positive caster on a CCSB and 0.49° on a CCLB.
If I had to guess, the clowns at ford designed the caster for an in-service loaded condition, which is basically what you’re configuring the truck into by chopping down the blocks.
I’ve been thinking about lowering the rear and adding a 1” BDS kit up front on my truck instead of the 2 1/2” Carli front I was previously thinking. Anyone know what the castor affect of that would be? I’d like to have an idea of what castor shims I would need prior to getting an alignment. This is on a 18 f350 6.7 ccsb. I will be adding air bags at the same time. Thanks for any input.
I’ve been thinking about lowering the rear and adding a 1” BDS kit up front on my truck instead of the 2 1/2” Carli front I was previously thinking. Anyone know what the castor affect of that would be? I’d like to have an idea of what castor shims I would need prior to getting an alignment. This is on a 18 f350 6.7 ccsb. I will be adding air bags at the same time. Thanks for any input.
The caster change caused by lowering the rear is easy to calc as you're just pivoting the frame on the front axle. Raising the front complicates it a bit as now you need to calc the pivoting of the radius arms. What's the distance from the axle c/l to the radius arm pivot point?
You can see why raising the front throws off the caster as much as it does due to the short radius arms compared to raising or lowering the rear which is determined by the wheelbase.
I lowered my rear yesterday. Went from stock 3 1/4" blocks to 2" blocks from pmfsuspension.com (with new u-bolts & nuts). Happy with the results. Stance is still raked, but not as extreme. And as others have mentioned, there does seem to be some minor ride improvement.
Thanks to cficare and his awesome write-up with pics. I already had a 3-ton floor jack and 6-ton jackstands, but not the pedestals. His write-up helped a bunch. I built pedestals similar to his (only one pair) and they were needed. My pedestal dimensions were 12"x10.5"x6.5" and used all of a single 8' 2x4 for each one. The 12" length fit my Big Red jackstand dimensions well. Also from his write-up, I had a 24mm deep socket, but it was a bit loose on the nuts, so bought a 15/16" deep socket and it fit better. https://www.ford-trucks.com/forums/1...l#post17607426
Took me a bit over an hour and half to get it done. Before breaking the nuts, I spent extra time trying to figure out how high to jack the axle before settling onto the jackstands leaving an inch or so with the tires off the ground, for lowering the axle to remove the current blocks. Had to get the wheels a good 5 or 6 inches off the ground. Jackstands were positioned under the forward leaf spring bolts. Seemed a better spot than on the box frame or further back on the hitch frame. Big Red jackstands were 6 teeth showing, and on the pedestals, reached a height of 27". Jacking under the pumpkin (I know), I used just about all the 18" height the floor jack was capable of. I added a block of 3x3 wood to the floor jack pad to get the axle high enough to release the jackstands when done.
Breaking the nuts wasn't too bad with my 18" breaker bar. I don't think they were torqued to 185lbs. After a few turns with the breaker bar, I switched to my 12" ratchet for faster removal (I need air-tools). Everything went smoothly following cficare's write-up. It took a bit of muscle to get the new nuts torqued to 185lbs.
After the job was done, the sun was going down, so I found a clean wall to pull up to to adjust the headlights. Also per cficare's notes, I positioned the front axle 160" from the wall, chalked the headlight beam on the wall, and used a 6mm hex on the white nylon bolts to lower the headlights roughly 1 1/4" to counter the rear lowering. Haven't driven at night enough yet to know if that was good enough.
Will add before & after pics of stance when I get a chance.
Thanks cficare!
You'll find those wood pedestals come in handy for all sorts of things around the garage. I even helped move a neighbors small sailboat with them. Inverted the pedestals atop a moving dolly and the transom rested neatly in the gap of the (normally) bottom 2x4s. I also use them to raise the height of a trash can when cleaning / sharpening chainsaws at my workbench.
You broke the nuts loose with only an 18" breaker bar? You must be one strong dude. With half of the jack handle slipped over my breaker bar, I was having a tough time using almost 4' of leverage. The torque wrench I bought for reinstallation is about 30" long (I don't recall the exact length).
FWIW, I have since installed a pair of Torque air-bags for when the loads get a little heavy.
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