Sachs Shock Service

[Jakobi]

Going to try my hand at a Sachs shock tomorrow.

So, how now brown cow. I see they have no bleed port at all, no where to connect the vac pump to, and also run an ifp for the resevoir. Whats the best way to get into these things..

Off to download the manual

Any hints tips or tricks appreciated.

 

[Jakobi]

No hints. I don't like this shock one bit!

IFP has no threaded insert for removal. Had to remove the clicker assembly and use compressed air to pop it out. The shock has no bleed hole, so no good using the vac pump on these bad boys..

But the cream on the cake.. The top out spring retainer is fixed to the shaft, meaning to put a new bump stop, or seal head on it you have to remove the clevis.. which has no lock nut and won't come off easily! Dirty shock!

 

[swazi_matt]

I would like to follow this thread so please add some pics, i watched a guy install my race tech valve so may be able to remember how he did it (he did not vacume pump because he did not have one)

 

[Jakobi]

Its a Sachs for a 07 TE450 Husky, but very likely the same setup that the gassers use. I can take a few pics of it all pulled down. I've put the clicker assembly back in again now, but valving, and ifp are still out. Had to order in a racetech shaft holder as trying to use anything home made wasn't holding firm enough to spin the clevis off the shaft.

Hand bleeding will be no issue at all. Fill the main chamber a bit, and insert the valving. Fill resevoir to top, slide the IFP/res seperator in and allow a little overflow. Drive it down to the required depth, which pushes fluid past the clicker stack/bleed. Stroke the shaft a few times and bleed until no more bubbles surface. Top up the main chamber and push the seal head in, install the snap ring. Then install the end cap, snap ring, and charge.

 

[Jakobi]

Heres a pic for you Matt

And some of the other fun I've had playing with this bike.. Beware the second hand owner.

 

[gasmonkey]

Holy crap,what butchery.

 

[Simmo737]

The biggest problem with Sachs is the energizer o ring flattening and the shock loosing damping because of it, you need to step cut the piston band and replace with a viton o ring, the ltr website used (prolly still does) have the details, the shock really benefits from a gold valve as it wears the band less and seals better, the step cut should back pressure the band as well to aid sealing. The upper valves have minimal variation as well so compression clickers dont do much. The base (rebound) valve becomes compression fine tube as we'll. the one way valve in the base causes some harshness, you can remove it by removing the first of two nuts on the end of the shaft, remove the spring and ball, you will have to play with the compression damping after that, lots of stacks to 'start point' on husky cafe. Cheers

 

[Jakobi]

This ones off a 07 TE450 Simmo. 16mm shaft. No rebound check valve.

I'm not sure if this particular shock suffers the fade due to the piston ring. The owner advised rear end was harsh/hard. The rebound circuit was closed and crossing over into the compression. It was like a rock. Add in the state of the swingarm bearings (now replaced) and the dry linkage bearings (now greased), and that at ome stage there was contact between the shock bolt and tierods, and well.. you get the idea.

 

[twowheels]

The owner advised rear end was harsh/hard.

Heh

 

[Simmo737]

I reckon if you can get hold of a new oring, wack it in and do the step cut, it seems to affect all Sachs shocks and may be to do with the steel body.

Ps what a mess!

 

[Jakobi]

Can you elaborate more on the step cut?

 

[swazi_matt]

A bit of info here

http://www.lt-racing.com/html/sachs_upgrades.html

 

[Jakobi]

Had a good read of that. Thanks Matt.

Had a quick read and see what a step cut is (not on LTR site). Any issues with using an angle cut? Either way, I'll have a closer look and try and work out which piston band they have on this particular model.

 

[Simmo737]

A step cut is like looking at a set of steps sideon, you cut the piston band down to half way, then across then down so it intertwines when held together.

Cheers.

 

[Jakobi]

Yep yep. Worked it out with some light reading Thanks Simmo

 

[Synergy-Seals]

Jacobi. I have the 16mm sachs shock seal and the swingarm bearing kit!

Rob
209-938-nine seven 2 six

 

[swazi_matt]

Hey jake why do you say it is not possible to vacuum bleed the shock?
How is it different on other shocks? (Pls answer with pics;-)

 

[Jakobi]

Thanks Rob, I had some swingarm bearings here and the bushings came up ok after some cleaning. Ended up replacing the tie rod portion of the linkage.

The Sachs shock was really quite easy to hand bleed, and I used the seal head to set the height of the res piston. I also used the vac pump to pull any air from the fluid before pumping it into the shock for hand bleeding.

In regards to the vac pump Matt, you have to be able to fully assemble the shock dry, and then connect the vacuum pump lines to the shock. This means you either need a bleed port (just a threaded hole somewhere on the shock body, ususally near the top eye), or you need to bolt up an adapter plate to the resevoir and fill from there. Using the later way, when completed you remove the adapter and then drop the bladder into the res and allow some oil to overflow and no air is trapped. Due to the Sachs using an internal floating piston to separate the N2 and oil, you can't get it in there at the right height using this method.

 

[5valve]

Any special tool needed, to hold the seal body in place, while unscrewing the 4 hole seal cover?
There is no way for it to give and it wouldnt be in my interest to scar the body.

 

[swazi_matt]

Possibly try a strap tool like you use on car oil filters?