Sachs Shock Service

[Jakobi]

I haven't seen one that looks the same as those pictures. What does the other side look like?

If you do indeed need to remove that inner section the right tools will be a clamp that accepts the OD of the seal head, and a pin spanner or custom tool that fits well.

From memory, every Sachs seal head I have seen you simply need to remove the snap ring on the back side and everything comes apart.

 

[5valve]

Oil filter wrench with strap did cross my mind, but it has a lever with knurled area for better contact on filter surface,
so would need to put protective rubber beneath the wrench and hope it would hold the torque.

I also hoped for the easy type body, with washer only, but was once again proved wrong.

Making OD seal head tool would require yet another machinist work, probably out of non slipery hard plastic.

I found that RXV has the same type seal head, but no one yet has opened it.
http://i1231.photobucket.com/albums/ee517/wilmar130/Aprilia SXV/IMG_2582.jpg

This is the other side after removing rubber stop. Bushing also calls for replacement.

 

[5valve]

Managed.
Some tweaks to the tool and a firm grip with adjustable pliers on a non contact surface.
Seals measure:
dust 22 - 16 - 3/4??
oil 24.4 - 16 - 3.4
bushing 18 - 16 - 11.9

Is this the same for all 16mm shaft shocks?

This material is impossible to come by in my country, will need a drive to Italy.

 

[Jakobi]

With the style that uses a flat plate and no top out spring I would simply source a complete SKF seal head. I used one in another style but had to machine a spacer and remove the top out spring.

 

[Jakobi]

http://www.suspensionworld.eu/shops/suspensionworld/cms/skf-shock-seal-head.pdf

Measure it up. I'd say Beta listing would be right. Quite a few variations of these Sachs units

 

[5valve]

Thanks. I see gas is actually listed in TM section.

 

[Jakobi]

Measure the dimensions of your seal head. The Part numbers inc ID/OD/Height
ie. 16-50-24

I'm betting your shock will use those above. The ones with the top out spring use the 15mm seal head. Any changes here will be reflected in the shock length (which is even greater differences in chasis once the linkage is taken into effect).

 

[5valve]

OD 50 is the measurement being correct.
It's 26 high.
Presume that ID is measured with teflon bushing installed, making 16 ID also correct.

Since SKF is aftermarket, maybe their product is lower then OEM, thus the 15 height being correct (16 - 50 - 15)
You made me think now, since all sales advocate the 15 seal head for gasser, but the beta model being the closest to stock height.

 

[5valve]

Flashed my mind.
If I measure the height of the 50 OD area only, it gets us closer to 15.
This being correct or not..not sure any more.

 

[Jakobi]

You second pic is correct. There can be a few mms difference between the OEM and SKF in some situations. I compared a 300EXC piston which measured around 17mm, while SKF parts state 15mm.

As above, the Sachs shocks come in a variety of configurations. Some use a top out spring, some use a larger plate. All seem to use that stupid snap ring on the shaft which means you need to remove the clevis to access the bump stop (which isn't hard really).

Below is a pic of the seal head I pulled from a Husky WR125. From what I can gather, SKF have not manufactured seal heads for use with the Sachs variety that use a top out spring. In your case you should simply be able to source part 'SH-ZF-16-50-15' and it should be a simple install.

As you can see, this Husky Sachs used a much deeper seal head than yours. It was a 50mm OD, 16mm shaft. The nylon plate recessed into the seal head and locked into position with a circlip (resting on top in the pic) is where the stop out spring would ride.

Most tuners here (in Australia) and most likely in general, machine out the OEM seal head to accommodate either a KYB/Showa seal as they are cheap and easily available.

 

[5valve]

Took a different path today.
Visited two shops, got all the necessary parts for overhaul. Will be changing all seals, orings, even though they weren't leaking. Just a piece of mind.
Rod guide teflon bush 16x18x12 cost me 2.4 euros. It's dead standard.

Won't be changing valve bushing and oil/gas separator diphraghm guide. The latter is made from teflon only. It was measured OK.
They can produce it, but can't make a step cut, but rather at 45 angle.

Only problem occured with oil seal. I got the correct measurement of 24.5 OD, but it is firmer and has only one sealing edge.
If you look at OEM, it is rubbery soft and besides sealing edge, it has two extra grooves on the sliding area.
Non oem is also a bit higher at 5mm, but it doesn't affect its function even with original separating washer installed.

No matter, will be installing what I got, and if leaking occurs, will go for KYB seal, and have the seal head machined as per your advice.

I did all of this, because waiting time to get stock or aftermarket parts for sachs is unreasonable.