'67 Bilstein replace Boge front stuts - - rubber bump stop

[red911]

Hello all,

I got some Bilstein P36-0111 front strut inserts to replace the Boge's that I removed. The struts did not come with rubber bump stops on the inside of the top metal cylinder cover for the struts.

The Boge's had a rubber bump stop.

When I did my '66 coupe, I received rubber bump stops and I cut off one of the three rubber stops to give me some more rebound.

Pelican tech board is inconclusive and many have the same question there, but when their board listers called Bilstein, they could not have this clarified.

The car will not be lowered.

Do I need the rubber bump stops? Are there internal ones in the Bilstein's as some discuss at Pelican?

Thanks in advance, Tom

[Flieger]

I have also heard that the bump stops are internal. I do not know if there is a difference between the Bilsteins for Bilstein struts and the Bilsteins for Boge struts.

[chris_seven]

There is a significant difference between the insert fitted into a Bilstein Strut and the insert used to convert a Boge unit.

The Boge damper is a conventional telescopic strut and has a convetional style of insert



I would imagine that the piston rod is 15-18mm diameter and will operate exactly as the Boge unit.

The body of the insrt will locate radially in the bottom of the leg and will be held in place with a screwed cap at the top of the leg.

The piston rod will move with wheel movement exactly as the Boge unit.

This damper will not have an internal Bump Stop and I would try to fit the one you remove from the Boge damper. If not Superflex or Powerflex make universal parts that you could use.

The Bilstein strut that we all know an love has a significantly different design where the insert is 'inverted'.

The body of the insert has a a diameter of 40mm and a ground finish. The piston rod is about 9 - 10 mm diameter.

Inside the strut leg there are two DU bushes that allow the 40mm dia insert to slide up and down inside the body of the strut.

The piston rod is secured to the sturt body using a roll pin at the base of the leg



In effect the 'telescopic' part of the strut now has a 40mm dia and a much improved bending stiffness so there is much less binding under braking when the bending forces generated tend to cause a conventional damper to stick in its bushes and some patter can result.

The bump stop is fitted onto the piston rod as the cavity inside the leg is dry - hence the description of an internal bump stop.

Unfortunately it is not possible to fit this type of insert to an early leg without re-tubing the body.

We have some honed bore tubes of the correct size to accept the 40mm insert and DU bushes and we use an insert that has a threaded piston rod to allow it top be attached to the stub axle.

[304065]

Chris, great explanation of the "upside-down" Bilstein design.

What is DU? (I read that I see "depleted Uranium. . . )

[chris_seven]

a DU bush is a Glacier Metal backed polymer bush that can run dry or run with slight lubrication.

There is a whole series

http://www.ggbearings.com/product_group_01.php

The Du Series are here:

http://www.ggbearings.com/_pdf/literature/1345.pdf

We tend to buy them directly from the manufacturer as the ones Bilstein supply are now quite short compared to early production - they are now only 25mm long where they use to be 40mm.

There are also some newer materials available but the DU Series has worked well for a long time.

[red911]

Hello All,

I received an email message from Chuck Moreland, Elephant Racing who said:

"Hi Tom,

Bilsteins for boge have the bump stops internally. This is very different than a boge insert, but nothing to worry about.

The bilstein bump stop is at the bottom of the insert, inside the tube (green or yellow).

regards,

Chuck Moreland
www.elephantracing.com
1043 Garland Ave Unit B
San Jose, CA 95126
408-297-2789"


Then I confirmed that no rubber bump stop on the insert shaft was needed and his response was:

Correct, install just as they come from the box.

I had asked Chuck about the rubber ring that just went over the threads and asked what to do with that, Chuck said:

"Remove the rubber ring. Its purpose is to hold the metal cover on in shipping/handling."


I hope this helps and I am always amazed at the quality vendors like Chuck and Elephant Racing that are out there ready to assist us.

Tom