KW HAS with factory bumpstop. Is this ok?

[JD1100]

While changing the ride height today, I noticed that the rear bumpstop is still the BMW bumpstop on my KW HAS. Is this a problem ?

I bought the car used a month ago and this is the first time I've had the wheels off. I'm wondering if I should order the KW bump stops and replace them, or is it ok to run the BMW bump stops ?

Anyone else have this issue ?


This is on an F82 M4

[Jwild90]

you should be okay, I'm running m perf has kit and only difference is has kit bump stop is shorter to allow possible more travel with out hitting bump stop. it's only there to stop it from bottoming the inner piston so regular bump stop should still work, and honestly unless you full send like dukes of hazard doubt it will ever hit the bump stops.

[horsepower_and_hounds]

Yea a lot of shops don't take the time to change the rears. I didn't either I just measured the ones in the kit then trimmed the top off while it was on the shock that way it would still remain up in the top hat and also retain the shock protector....boom

How are you changing the rear ride height? On mine you have to take the adjuster out and re-install it each time cuz it spins in the body. What a PITA and stupid design. I need to lower the rear a bit more..I only have 1.5 turns left to go down then I am out of adjustment

[RElias21]

The shop that installed my MP HAS didn't even bother changing the rear bump stops. I noticed while adjusting the height and before I went back for the alignment.

FWIW, they did it for me without issue when I went back, but I realized then that they didn't just overlook it the first time but thought it was a useless swap based on their experience.

I just wanted the kit with all the parts provided, but 99% of the time it's probably pointless. I guess, if anything, it may come into play more the further you lower it?

[RElias21]

Originally Posted by horsepower_and_hounds

Yea a lot of shops don't take the time to change the rears. I didn't either I just measured the ones in the kit then trimmed the top off while it was on the shock that way it would still remain up in the top hat and also retain the shock protector....boom

How are you changing the rear ride height? On mine you have to take the adjuster out and re-install it each time cuz it spins in the body. What a PITA and stupid design. I need to lower the rear a bit more..I only have 1.5 turns left to go down then I am out of adjustment

I agree that both the MP HAS and KW kits are really poorly designed with respect to adjusting the rears. I guess the MP HAS may be easier to fix, since it sits at the top.

I ended up getting an oil filter wrench and gripping the top of the threaded piece while twisting the spindle with the key. It was super difficult and I really chewed up the top of the threaded portion (not the threads themselves).

I figured, worst case, that part is hopefully replaceable.

Ultimately though, I set it at a rear heigh I don't think I will be adjusting. It was more about getting it to the stance I wanted and just leaving it alone.

[JD1100]

Ok. Thanks for the replies guys. Thats what I suspected regarding the bumpstop.
I bought the car used and the person before me had a shop in San Francisco do it It's far away from where I live (LA), or else I would probably take it to them and try to get them to change it. I'll most likely leave it with the BMW stop in place.

The reason I am adjusting it higher is because the ride was terrible, felt like it was riding on the bumpstop. When I took the wheel off, I could see it was adjusted as low as it could go on the spring pertch. Now that I see the factory bumpstp was left in place it makes sense I'm pretty sure it was riding on the bumpstop.

After raising the height about 10mm the ride has improved.

Originally Posted by RElias21

I agree that both the MP HAS and KW kits are really poorly designed with respect to adjusting the rears. I guess the MP HAS may be easier to fix, since it sits at the top.

I ended up getting an oil filter wrench and gripping the top of the threaded piece while twisting the spindle with the key. It was super difficult and I really chewed up the top of the threaded portion (not the threads themselves).

I figured, worst case, that part is hopefully replaceable.

Ultimately though, I set it at a rear heigh I don't think I will be adjusting. It was more about getting it to the stance I wanted and just leaving it alone.

Regarding the spinning top adjuster, I found a very good solution.
Here is what I did. .... Take a long socket extension and place it through the hole at the bottom of spring and put a small cloth or piece of cardboard between the end of the extension and the bottom of the perch. Then use a floor jack to push it up and put pressure on the perch so it doesn't spin. This worked perfectly I got the idea from another member who posted about this.

https://f80.bimmerpost.com/forums/sh...4&postcount=16

[Jwild90]

yea its extra step to replace bump stops but honestly it's held in by 3 torx up top and one bolt on lower control arm... literally takes less then 5 min to take it off the car since you are alredy doing the springs and replace bump stops... but yea 99% of times its its not doing anything it was designed to do... lol

[JD1100]

Does anyone know if its possible to remove the rear shock with out unbolting the outer lower control arm bolt? I'd like to avoid having to get a re-alignment.

I'm only trying to replace the bumpstop for the rear shock. I dont need to remove the spring, etc. I believe the outer bolt for the lower control arm is where the alignment cams are. Is it possible to do this with out touching that ?

[JD1100]

FYI - update .

So I did end up ordering the rear bumpstops from KW.. I was easily able to remove the rear shocks with out unbolting the control arms; you just need to compress the shock by hand a few inches and remove it before it expands again.

After doing this , I was able to lower the rear a bit more with out the bumpstops being hit frequently.

The shop who originally installed the suspension was lazy and unprofessional not to completely install everything from the kit. Make sure you have a reputable shop do work on your … or do it yourself if you have the space/tools.