I recently installed a set downey 3 1/2" rear leaf springs and now my slip yoke bottoms out on large bumps. When I cross referenced the part numbers on their website, it appeared that the sent me the wrong springs.

When I talked to downey, they told me the numbers on the site aren't the same as the numbers they use in the warehouse, and that they wanted me to take pictures and send them to them. A few hours later I get a call saying that the springs where properly installed (duh) and they didn't see any reason for the yoke to bottom out, other than the previous owner may have extended the driveshaft.

If the previous owner extended the driveshaft, why would I be having this problem now? When I bought the truck, I replaced the blocks it had on it, with downey's add a leaf and never had a problem. I later discovered a broken leaf so I purchased the new ones.

Help!

 

One reason might be that with blocks, when you bottom out the springs on the bumpstops, the blocks do not compress, so it leave the axle X" from the bumpstops (where X is the height of the blocks). Now put on lift springs and when they bottom out on the bumpstops, the axle compresses that much (X") farther than with the blocks. One simple option is to raise the bumpstops up 1" up to X" taller until it does not bottom out. Also, you could check the front spring eye to center pin measurements on the old and new springs and see if they are significantly different.

 

But it didn't bottom out when I had the add a leaf installed.

 

Well one of two options, either the AAL was stiff enough to keep the old spring pack from bottoming out or the new springs moved the axle farther forward due to being shorter on the front half.

 

What is the correct way to measure springs? Just a straight measurement from the center of the front bolt to the centering pin, or do you follow the curve of the spring?

 

As I noted, you measure along the arc of the spring. You want to know how long the spring will be when it is flattened out because that is what shape it is in when the springs bottom out. Lift springs will have more arch than stock springs but when they flatten out is what you care about. So use a tape measure and bend it to roughly follow the curve of the spring.

 

Downey is blaming Toyota for not giving my slip yoke enough travel.

They gave me three options to fix it.

A) Drill a hole 1" forward on the spring pirch.
B) See if the carrier bearing assembly can be adjusted forward.
C) Shorten the driveshaft.

WTF?

 

Or Downey placed the center pin on their springs too close to the front spring eye, or at least closer than the stock Toyota springs.

Another option is a bolt-on spring perch relocation plate. You set the plate on the spring perch, pin into the existing center hole then you slip the spring center pin into the new hole in the plate, offset 3/4" or 1" from the existing location:

- http://www.4crawler.com/4x4/ForSale/...elocationPlate



Or as I noted earlier, raise your bumpstops an inch or so.

 

this might sound silly but did ya put the springs on the right way (like puting them on back wards ? making the center pin face further foward ? i had done this on a full size cherokee once up front .. turned out i liked the fact it moved my axle foward 2 more inches . helped out alot climbing over crap .. just my 2 cents .

 

They were installed properly.

 

Have you compared the front half measurements of the old and new springs?

 

I remember having to push the axel about 1/2" to 3/4" forward.

I disposed of the springs before I realized there was a problem. DOH!

 

Either redrilling a new hole in the spring perch or installing a set of axle relocation plates (as shown above) would move the axle back to the original location and eliminate the bottoming out.

 

That's what I planned on doing this weekend. Thanks.

 

What are your thoughts on running those relocation plates with a pinion shim?

 

Should be no real problem, although best to only have one thing between the spring and axle to reduce the likelyhood of the parts falling out if something happens to them.
It is also possible to incorporate a pinion angle taper into the relocation plate. Or you could tack weld the plate to the perch and then just use the shim normally.

 

back on the gen 1 driveshafts, we could cut about .5 inches off the end of the inner splines. Don't know about your truck. That might be all it takes too give you enough room, but you'll have less usable slip if you cut it. I say axle relocating plates or just redrill your perches back a bit.

Do something because one of these times you are going to slam your driveshaft hard enough to break your Tcase.