Bottoming Front End

[DaveHess]

About 8 years ago, I installed Bilstein 5100's on all four corners of my pickup. I called Geno's and was told these shocks worked on stock suspension up to I think it was 2" of lift. In any case, my pickup is stock. Ever since I put those shocks on, I have had an issue with the front suspension feeling like it bottoms out on certain type bumps in the road. The easiest type of bump that we are familiar is parking lot speed bumps. I literally have to a super crawl over these or I get a bone jarring thud from what feels like the driver' side front tire. On the road it is harder to tell if it is going to happen or not but railroad crossings have to be taken carefully.

This problem did not exist before the shock change. I have researched the difference between the 5100's and the 4600's (yellow/blue boot) and found that the compressed length of the 4600 is something like an inch and half shorter than the 5100. My thoughts have been that I was bottoming out the shock. I have been under this pickup an enormous amount of times inspecting the front suspension and cannot find where any components are hitting each other so I am left with the front shocks being the only suspect items. My other thought was since I feel like it is the driver's side (this was the side that was a 3 hour ordeal to change), are the shock towers indexed in any way that I could have installed it wrong and changed the shock geometry to the rest of the suspension? Is it even possible that I am bottoming out a 5100 shock? The tires are not showing any cupping as might be seen with a bad shock or any other unusual wear. I run all of my tires at 70PSI and rotate them every 7,000 miles.

Any thoughts guys???

 

[JR]

How many miles on the shocks?
In 8 years time they would be past worn out on my truck but everybody's uses/mileage is different.

Its possible you got a bad shock to begin with but under normal conditions should not be able to bottom them out.

 

[DaveHess]

JR, these shocks are lifetime warranted so I am operating under the assumption they are still "good". I baby this pickup so it has been about 50K (85K total miles) on these shocks. I noticed this problem shortly after installing the 5100's. The way I see this, those front 5100's need to come out and install the new 4600's I bought from Genos. Part of my question was could I have made a mistake in my installation. The driver's side is a little labor intensive to replace the shock and I am 8 years older now, so.....

 

[Prairie Dog]

I have the same shocks and they perform great - never experienced anything like you describe.
I would take them off and see if any of them are limp/worn out.

 

[lpennock]

To check if you are bottoming out a shock. Check the distance between the bumpstop and the axle. Then check amount of rod showing on the shock. if there isn't more rod than the cleanance to the bumpstop you have a issue.

If you have the cover over the rod, mark the shock sitting normal. Then jack up the truck to extend the shock and see how much of the shock is inside the cover add about 1/4" for the distance inside the boot to were the rod bottoms out.

 

[DaveHess]

I do have the boot on the shock. But I must confess, your instructions are a bit hard to follow. Could you rewrite them for me with more explanation? If you have the time. Thanks.

 

[Badunit]

I put 5100's (from Geno's) on the front of my 2003 when it was new. It would bottom out over speed bumps with the stock shocks. The 5100's made a huge difference. I never had a problem with them.

 

[lpennock]

I do have the boot on the shock. But I must confess, your instructions are a bit hard to follow. Could you rewrite them for me with more explanation? If you have the time. Thanks.

Sorry I'll try again.
Measurement 1. Distance from bump stop to the axle
Measurement 2. is amount of rod available before shock is fully compressed.

If Measurement 2 is less than Measurement 1 then you may bottom shock on bumps.

With the cover on the shock determining measurement 2 is a bit harder.
a. mark the shock where the bottom of the cover is at on the shock body (sharpie or pencil works good)
b. jack up the truck to extend the shock
c. you should now see the top of the shock body under the cover
The distance from your mark to the top of the shock body is how far the top of the body was inside the shield.
d. Subtract the length you measured in c from the length of the cover. The remainder is the the length of the rod. to use as measurement 2.

 

[Regcabguy]

I put 5100's (from Geno's) on the front of my 2003 when it was new. It would bottom out over speed bumps with the stock shocks. The 5100's made a huge difference. I never had a problem with them.

Ditto on my '07. Unladen it would bottom out easily. Load the Northstar on there and it was a disaster.
Aftermarket to the rescue.

 

[gofastman1]

spring? check left to right ride height.

 

[DaveHess]

The ride height is the same between left and right. I have been under the truck again this week and looked everywhere I could get my head around and anywhere where there could be contact and I cannot find any contact evidence. The tires are not displaying any unusual wear patterns either. No cupping or feathering on either edge of either tire.

 

[seafish]

Can you still read the part #s on the Bisteins after 8 years…is it possible that they sold you ones for a lifted instead of stock height truck??

 

[DaveHess]

Seafish, I'll have to take a look there. This truck doesn't see too many adverse weather days.

 

[DaveHess]

Ok, so I folded and bought a set of Timbrens for the front of the pickup. While I am under there installing them, I found my contact point. I have a PML front differential cover on my 9.25". As you look at this cover from the front looking aft, there are two sets of rows of cooling fins separated by the "bulge" for the ring gear. The left side (passenger), second fin from the top on the outside edge about 1/4" in was shiny and a little hammered. Directly above is the center link and sure enough the paint was scuffed above the general area of the cover fin. Like I said in the original post, this did not happen all the time and when it did to it sounded like a shock was coming through the floor board. In hindsight it was more like a hammer tap but to me...... well, I worry about everything as it is and there should not have been any noise coming from up front.

As a side note, I am kind of digging the front Timbrens. I also installed rear ones at the same time. Had to remove the spacer but in doing so there is about 5/8" of an inch gap between the axle and Timbren.

 

[mfurrh55]

I put front air shocks on mine,Monte