Blistein HD Bump Stop Mod

[ssbtech]

Well one side of the screw broke right off so I ground a new slot in the bolt. That too rounded out. I did get the shaft to turn about 1/4 turn but it's refusing to budge any more.

 

I'll just have to keep the bumpstop in.

[ssbtech]

I've dropped it off at a welding/machine shop to see if there's anything they can do. I'm not too interested in spending another $250 right now to replace a brand new strut.

[SBT]

They can likely weld a nut to the end of it and at least get it started that way. I think the inserts are like $60.00 plus shipment from Bilstein in Poway, CA. That might be the way to go, if you're going to pursue the bumpstop mod.

[ssbtech]

I'll see what he comes up with tomorrow.

 

I inquired about welding some sort of screw head onto it but he was concerned with over heating it. He's going to try to cut a new groove into it.

 

This thing is gorilla tight. After giving it all I could with vise grips on a screwdriver I pulled out the cordless impact driver. I know there's risk of snapping the road doing this (it was already buggered up), but it just snapped the hardened impact driver bit instead

[ssbtech]

They didn't get a chance to work on it yesterday so I called for an update this morning.

 

He's reluctant to weld anything onto it with the risk of the rod wicking heat to the oil/gas cylinder.

 

I guess I'll know later what happens.

[ssbtech]

Picked it up today. Couldn't get it to move. They refused to do any welding on it because they're worried about the piston rod carrying heat to the oil and gas.

 

He cut a new slot into the end but it just crumbled when he tried to turn it. I guess it's a hardened metel and doesn't flex much.

 

$280 to the garbage.

[BarManBean]

I'll see what he comes up with tomorrow.

 

I inquired about welding some sort of screw head onto it but he was concerned with over heating it. He's going to try to cut a new groove into it.

 

This thing is gorilla tight. After giving it all I could with vise grips on a screwdriver I pulled out the cordless impact driver. I know there's risk of snapping the road doing this (it was already buggered up), but it just snapped the hardened impact driver bit instead

 

For the future, anytime you are using a screwdrive-style bit, you should probably be using an actual impact driver that you hit with a hammer. It's designed to both hammer in the bit and attempt to turn the bolt / break the bolt loose at the exact same time. You cant get the same effect with an air / electric tool because the bits tent to want to slip out or the distance over which the torque is applies just snaps the bit.

 

Sorry for your troubles here though, sounds rough

[ssbtech]

Well my first mistake was assuming it wasn't gorilla tight. Knowing that the top nut only gets torqued to 41ft/lbs and the R/H strut came apart with ease, I assumed that the left one would too.

 

Slot screwdrivers have a taper to them and that taper forced the screwdriver back out of the slot as I didn't anticipate having to put so much pressure on it. Clearly a 1/4" screwdriver wasn't up to the challenge.

 

I upgraded to a 3/8" screwdriver with a hex shaft, clamped some vice grips on it and put my weight on the butt of the screwdriver. Turned with the vice grips and the thing still twisted out. Subsequent attempts just screwed the shaft up.

 

Here's an idea, terminate the end of the shaft with a hex instead of a slot. Germans

 

I know using an impact driver for the top nut is a no-no. Any suggestions for the bottom one so I don't end up throwing away another brand new strut?

[BAC5.2]

Rent an impact screw driver. It's a small device that turns a screw driver head when you hit the butt with a hammer:

 

http://www.autozone.com/autozone/accessories/Tools-Garage-and-Equipment/Impact-Driver-Set/_/N-25dw?switch=true

 

And don't use a low-energy heat source. You want to heat the body up quickly, before the shaft heats up.

[ssbtech]

There's a little less than the nut's width of thread left exposed below the strut body.

 

At this point if I can just get ths shok out of the body I could re-use the body. That would save me some money.

 

I think the machine shop was trying to preserve the threads on the shaft but if I can cut a slot in I might have another go at pulling it out.

 

In hindsight I probably should have used a non-tapered slot screwdriver. The taper just puts more force at the very tip of the screw head.

[BarManBean]

This is what you're looking for, BTW:

 

http://conservatoryadvice.files.wordpress.com/2010/07/impact-driver.jpg

 

Each time you hit the butt with a hammer, it will cause the driver bit to rotate with a good amount of force.

[ssbtech]

Thanks.

 

I cut a new groove in it today and tried again with my 18v impact gun. The hardened impact bit bit broke at the same time the rod cracked again.

 

New strut has been ordered.

[BarManBean]

 

Just for the record, I think the action of a manual impact driver is much different than that of an electric / air impact tool. The driver will apply force one "instance" at a time where as an electric / air tool will try to do so repeatedly in rapid succession. Often times when using a manual driver you still have to hit it several times but after a while whatever you are working on will come loose.

 

Either way, some things will just never break loose. Frustrating.

[ssbtech]

I think Bilstein needs to check the torque calibration on the assembly line... or not hire steriod users.

 

In any event, anyone need a partially broken front left HD strut?

[Shines-1]

Great post guys!!!!

[ssbtech]

How about some anti seize on it when it goes back together?

[SBT]

This is what you're looking for, BTW:

 

http://conservatoryadvice.files.wordpress.com/2010/07/impact-driver.jpg

 

Each time you hit the butt with a hammer, it will cause the driver bit to rotate with a good amount of force.

 

Just make sure you have the ratchet set to the right direction. And I agree, why is this a slot and not a hex-head?

[BAC5.2]

Just make sure you have the ratchet set to the right direction. And I agree, why is this a slot and not a hex-head?

 

Because a socket cap hex head can get packed with debris, and an external hex costs much much more to make than a slot.

[SBT]

Good points, but, for a premium product, one expects a better-engineered design, especially given that these are rebuildable.

[ssbtech]

Or an accurate torque wrench on the left-strut assembly line

[ssbtech]

My 2nd brand new front-left strut showed up today and the insert came out with virtually no effort at all. Heck, the nut was tighter than the insert was.

 

Let's hope Bilstein's damping is more consistent from strut to strut than their assembly torque

[SBT]

Congrats.

[sperry]

Bump(stop) for an update...

 

Since I've got a set of Bilstein HDs and Pinks on order for my Outback, I thought I'd look into doing this mod on my struts prior to installing them.

 

Unfortunately, it doesn't look like RaceComp sells the shorter bumpstops any longer... at least they're not on the website, nor did I get a reply to my email asking about them. So I tossed an email over to FatCat Motorsports, since they're big on Bilstein's with their Miata suspensions (as well as Subarus, as I've come to find out).

 

Anyway, Shaikh (the suspension guru there) has cut down the internal bumpstops on LGT front struts, but then he adds back in a 3mm delrin packer.

 

Here's the important parts from my emails with him:

 

For the Subie, we have often simply cut the front bump stop down to about 30-40mm and used a 3mm packer as a supplement. Ideally, you'd take bump travel measurements with spring off and bump stop in place then see how much room there is for the front suspension to compress before the tire binds (usually what contacts first). Not as easy on a strut car but after removing the strut insert from the housing you can access the bump stop (we apply heat with a torch to melt the red threadlocker before insert removal).

 

You can follow that method and see what kind of bump stop length you need for yourself. I have some images and comments on my Cardomain page re: testing bump travel:

 

http://www.cardomain.com/ride/742393/1991-mazda-miata-mx-5/page-2/

 

<snip>

 

I think you will be safe with the bump stop mod I mentioned. A 3mm packer is essentially equivalent to about 10mm of uncompressed bump stop so it's added insurance once you've shortened. I bet you could easily go 30mm bump stop length + (2) 3mm packer and be fine in terms of total travel.

 

I bolded the important part. So, that seems like a legit, easy, and cheap (packers are $5 each) way to gain a little extra travel with the Bilstein HDs and lowering springs. Packers are available right off the FCM website: http://fatcatmotorsports.com/FCMstops_comp.htm#spacer Most of their stuff is geared towards Miatas (I have a set of their Elite coilovers on my '96 Miata and they're godly), but the packers should work on any struts.

 

And of course, if you'd rather have custom bumpstops, FCM sells a crapload of options (as you can see on their page), but if Shaikh says just to cut the original ones down, that's what I'm going to do.

[DeltaNu1142]

I'm in the same position as ssbtech. I have an impact driver & can't get the strut apart. I may try the stubby/vise/twist body approach for moah torque.

[DeltaNu1142]

I give up. My impact driver bit is visibly twisted, I've broken two screwdrivers, and my ears are ringing from repeated blows on the impact driver. I've folded the steel on the edges of the driver "face" so it's got a nice sharp ridge on it now.