Stock rear bump stop clearance?

[samert111]

Anyone know approx. what the factory rear bump stop clearance was on a 68 C10?

I'm trying to figure out if mine has been lowered some already. I have about 3" of clearance now.

[pjmoreland]

I'm thinking stock bump stop clearance is in the 6" - 7" range since my truck has 6" drop springs and I had less than 1" of bump stop clearance before I installed shorter bump stops. Maybe the drawing below could be used to figure it out. You could measure your tailgate height (stock 27-1/4") and subtract the diff clearance (stock 7-1/2") to see how close you are to 19-3/4". These measurements won't work well if your truck has a lot of rake (lower in the front).

[samert111]

Originally Posted by pjmoreland

I'm thinking stock bump stop clearance is in the 6" - 7" range since my truck has 6" drop springs and I had less than 1" of bump stop clearance before I installed shorter bump stops. Maybe the drawing below could be used to figure it out. You could measure your tailgate height (stock 27-1/4") and subtract the diff clearance (stock 7-1/2") to see how close you are to 19-3/4". These measurements won't work well if your truck has a lot of rake (lower in the front).

Thanks for the info. Unfortunately, my box is off a 90's model so I can't use the tailgate measurements in your diagram. I probably can use the measurement to the top of the cab tho.

If your estimate of 6-7 inches as stock is correct, then mine has already been dropped several inches but based off the tire clearance to wheel opening on the front compared to your image I'm not so sure now.

[pjmoreland]

I don't know what to think about that drawing from the brochure. My tailgate is 23-3/4" high with a 6" drop. On top of that, my tires are smaller in diameter than the factory tires. It doesn't add up. Photos from the sales brochure make the space between the tires and fender wells look much larger than in that drawing.

[Casper42]

Originally Posted by pjmoreland

I don't know what to think about that drawing from the brochure. My tailgate is 23-3/4" high with a 6" drop. On top of that, my tires are smaller in diameter than the factory tires. It doesn't add up. Photos from the sales brochure make the space between the tires and fender wells look much larger than in that drawing.

my '72 C10 tailgate is at 29 inches. its all stock suspension, but I have 275-60R 15 tires. I suspect that drawing measurements is a bone stock, no options 67 or 68. those seemed to sit more like cars than the later C10s...particularly those having heftier suspension options.

[Grumpy old man]

Originally Posted by samert111

Anyone know approx. what the factory rear bump stop clearance was on a 68 C10?

I'm trying to figure out if mine has been lowered some already. I have about 3" of clearance now.

Your truck has already been lowered some 4" ? . Your shocks are almost horizontal still using the stock upper shock locators , You have a later model bed on it so trying to get measurements off the bed won't work , you have to measure the suspension .My tailgate down measures 25 1/2" off the ground with a 29 " tire . 67 short wood bed with empty rear gas tank .

This first picture shows 7 1/2" between the top of the trailing arm and the bottom of the frame rail using 5" drop springs .

The second picture shows I used the earlier 63-66 ? lower shock mounts ,It's a better mount using double shear vs 67-72 single shear lower mount . and upper shock relocators .

[samert111]

Originally Posted by Grumpy old man

Your truck has already been lowered some 4" ?. Your shocks are almost horizontal still using the stock upper shock locators , You have a later model bed on it so trying to get measurements off the bed won't work, you have to measure the suspension. My tailgate down measures 25 1/2" off the ground with a 29 " tire. 67 short wood bed with empty rear gas tank.

This first picture shows 7 1/2" between the top of the trailing arm and the bottom of the frame rail using 5" drop springs.

I'm back home now for the summer and taking some suspension measurements and my frame to top of trailing arm is approx. 9" but hard to get an accurate measurement because the top trailing arm pad is not parallel to the frame rail. It looks like you're correct tho and I already have a 4" drop in the rear which also seems to correspond with the 6"-7" stock bump stock clearance mentioned earlier. The odd thing is that based on current ride height of the shocks it's riding right at 15" which appears to be the stock shock length.

To correct the rear shock angle I'm looking at relocating the rear shock with either the Tin Works or No limit kit that moves the rear shocks to behind the rear diff and the outside of the frame rail.

[samert111]

So after much searching for upper and lower shock mounts for my rear shocks to correct to extreme shock angle caused by the approx. 4" rear drop, I came up with modifying a set of Summit Racing rear shock relocation brackets ($55) to mount the shocks outside the frame rail and behind the rear diff. The upper mount was modified the most and now is mounted vertically bolted to the frame rail. The bottom mounts were reversed and switched sides to move the lower mount point to the inside of the trailing arms and behind the diff. The shocks are sitting vertical to the trailing arm mounting pad.

The trailing arms are a mess. The two halves at the rear diff mounting pad are shifted so the new lower shock mount plate is not sitting square. So looks like some new Summit tubular control arms are the next project.

Also installed the CPP front sway bar. Still have the drivers side rear shock to mount plus it's snowing here in Mi so haven't had chance for a test ride yet.