Sachs 115-066 Front Struts

[RSK540iA]

Greetings,

I recently imported a pair of Sachs 115-066 (BMW 31 31 1 092 284) front strut inserts for my E34 540i. After taking the car in to have them fitted the workshop manager phoned me telling me the Sachs inserts were 60mm SHORTER than the fitted KYB units. Thinking I had been sent the incorrect units I instructed them to go ahead and fit KYB units.

I've since contacted my supplier, and also checked on the Sachs website. The supplied Sachs units are apparently correct, they are in fact recommended for the 540i standard AND lowered chassis. Apparently they reach their full length once an internal bump-stop has been compressed after fitment.
1. Is this the case?
2. Has anyone had a similar experience when fitting these units?
3. Do they lower the ride height of the car after fitment?

I'm considering removing the KYB units and fitting the Sachs units.

If someone could shed some light on the matter I'd be most grateful.

[ThoreauHD]

Sachs are the OE shocks and they also work on lowered springs, such as eibach. I''ve had both sachs and kyb, on EO and eibach springs. It's a non-issue. In fact, I have kyb in the front and sachs in the back. My car is quite level with both pairs, with no bumpstop adjustment, so I'm not sure what they are going on about.

[Jehu]

While we're on struts and bump stops. Has anyone used the Powerflex Urethane Bump stops? First thought is they'd be way too hard..

[RSK540iA]

They mentioned there's some kind of internal 'bump-stop' which must be activated by compressing the unit before it reaches its standard height. My fear is that the KYB are 60mm longer than the Sachs units. I would have to compress the spring a helluva lot to accommodate the Sachs unit... and once I have, would the strut height be 60mm lower (car then sitting 60mm lower)?

[Blitzkrieg Bob]

I think what you are experiancing is the rod appears to be shorter due to an internal spring/bump stop keepimg the piston retracted without a coil spring on it.

I had to really compress the coil to get the top mount back on, but once under the load of the coil spring it will extend to the proper length.

[RSK540iA]

Yes, this is exactly what I'm experiencing! I just find it strange that the strut will be under such additional strain, considering it's shorter. Is the spring travel still the same? What happens when one goes over a 'high spot' in the road, does the spring extend to the correct length, or does the internal 'bump stop' prevent this?

It seems my fitment center has never come across these shocks, hence their advice to not fit them. I assume Sachs are a far better shock than KYB? Should I take the KYB units out and fit the Sachs units?

Thanks for all your tips.

[ThoreauHD]

While we're on struts and bump stops. Has anyone used the Powerflex Urethane Bump stops? First thought is they'd be way too hard..

I was keeping an eye on that company too. No need for them yet, but they seem to be adamant about there stuff not sucking, and how half-assing stuff like Bruno's subframe inserts is a bad idea/design. They seem to have alot of satisfied customers and make a good case. But that's got not much to do with a bumpstop. Honestly, if a bumpstop is stiff or very stiff, who's gonna know. I'm not jumping bridges in my car.

[Jehu]

I bottomed out the other day on a dip , heard the front left tire rub the wheel well.. I have looked and seen i have no more Bump stops,lol.. they're all rotted away.. It felt pretty hard and i wondered if putting a urethane bushing in there which is about 5-6" tall would just deliver that abrupt jolt all that much sooner where the OE spongey ones have alot of give.. I don't aim for such dips but they can come up on you awfully fast sometimes

[Blitzkrieg Bob]

it just that there is an internal spring the kkeps the rod from being extended without the load of the coil.