Top hat rubber gasket bulging, Bilstein 6112

I installed Bilstein 6112s a couple weeks ago, 4th setting, assembled them myself with new top hats.

Today I was measuring the ride height and noticed that the driver’s side rubber gasket between the coil and the top hat is bulging out from under the top hat. The other side doesn’t have this issue and looks perfect.

Do I need to get this fixed/reseated/reinstalled? What would cause this?

 

It is likely from assembly. The center of the top hat bushing has a lip that rides inside the inner diameter of the coil spring. Often times upon assembly it gets caught and isn't fully seated inside the coil spring.

 

This makes sense. I had a hell of a time getting one of them to seat in the center of the coil due to the spring curving an awful lot during compression.

Can this be remedied by compressing the spring while installed and reseating it against the top hat? Or does the coilover need to be removed to adjust? I’m also wondering if I need to replace the top hat if the gasket is this mashed. I assume I need to fix this.

 

I would remove from truck and start over to be safe. Maybe pay a shop to compress the coil spring so it goes in smooth.

My wall mounted spring compressor makes the job easy. I have tried doing 6112 with hand spring compressors, it's a PIA that way.

 

I assembled using this spring compressor stand at the hobby shop onboard my local base. Maybe I chose the wrong spots for the arms to sit, or otherwise did a poor job. It’s a nice stand though.

Definitely going to have a shop do the work. Thanks for the advice!

 

Both mine did that after I drove on the new suspension for a bit. Used brand new KYB top hats. No issues in 25k miles and I lightly wheel the truck too. The rubber seemed a bit softer on the KYB top hats. Boths coils were seated properly.

 

Look at all the customer reviews with pictures. Same thing. It's the force of the spring making it mushroom a bit. Even if you pull the suspension and try and reset the position it's still going to do the same thing. I bet the other side is doing the same thing but it's around the back side.

$29 KYB SM5640 - Mount Kit

Amazon.com: Customer reviews: KYB SM5640 - Mount Kit

 

I don’t know, there are tons of photos there of the KYB’s looking “normal” with no gasket pouring out. But yeah could be that it’s in the backside. I’m having a shop take a look at it. Wish I could tell whether or not the inside of the gasket is pinched as Super Dave said.

 

The tons of photos are either of the shock not installed yet or freshly put on the truck. The bulging doesn't happen until you drive on them for a bit. I promise you they are seated right.

 

So three weeks after install only the one bushing/gasket is bulging. Definitely an install error.

I’m buying a new top hat and having a local shop reseat with new tophat. Just in case the bushing/gasket has become permanently deformed from pinching. Quoted an hour of labor, not bad.

 

Did this end up getting fixed after you brought it into the shop? Or did the shop confirm it was not installed correctly? I just installed a KYB top hat today and it looks exactly the same as your photo.

Thanks

 

What shocks and coils did you install? Some do have a clocked position, some don’t.

What I found out is that my coils were not seated against the top hats quite properly. It’s hard to describe verbally but there’s a potion of the top hat that has to fit inside the coil, like an insert. The machine I used to compress the springs did not compress them totally vertically and so the top hat did not seat properly inside the top of the coil. A shop reseated with a better compressor machine and they were perfect.

 

I installed Bilstein 4600 shocks with the stock spring. The truck is a 2015 prerunner TRD sport. I didn't notice any clocking features, but the inside of the KYB top hat had a lip that perhaps the spring didn't seat on correctly.

 

I believe the 5100’s have a clocking position not sure. My 6112’s did not, confirmed with Bilstein. The top hats definitely have a lip. If the coil doesn’t seat against the top hat correctly it looks like crap and is obvious. I can send a pic of my coilovers against the top hat if that helps you. There’s a little bit of conformity to the top of the coilover but it’s minor.

 

Yeah a picture would be helpful, thank you. I’ll probably just disassemble it tomorrow and reinstall it. I haven’t driven it yet so I’m thinking the top hat is probably still fine.

 

Consider taking to a shop that has proper compression equipment, floor mounted or even wall mounted. An independent shop shouldn’t charge much to reseat.

I’ll post some pics of mine tomorrow. A shop reseated them and they’re perfect now.

 

Well today I took it all apart and the top hat still looked good. I really wasn't able to tell if anything was clocked incorrectly. When I reinstalled it I had a helper compress the spring very slowly as I guided the inside diameter of it over the lip of the top hat, and that seemed to have done the trick. I took the truck out for a drive and the top hat still looks good. Yesterday when the hat looked messed up it happened as soon as I lowered the truck back on the ground and drove it back and forth a few feet. Today I also used an inspection mirror to check around the back side of the top hat to see if the pad was bulged in the back, but I didn't see anything abnormal.