E21 Front Struts

[320iBimmer]

Anyone have any input for changing front struts, i.e. tools necessary, places to buy struts, what the cost is, level of expertise etc.

Thanks much

[Layne]

I assume you want to replace the shocks? The Hayne's manual should help. It takes some effort to seperate the ball joints, and you'll need some spring compressers. There's plenty of places to buy the shocks, cost depends on what you want, about $250 for goodstock replacements or about $400 for high performance ones (thats for all 4). Or did you actually need struts? Ie: they were damaged in an accident.

[blitzed310]

I assume you want to replace the shocks? The Hayne's manual should help. It takes some effort to seperate the ball joints, and you'll need some spring compressers. There's plenty of places to buy the shocks, cost depends on what you want, about $250 for goodstock replacements or about $400 for high performance ones (thats for all 4). Or did you actually need struts? Ie: they were damaged in an accident.

He said struts, not shocks. And there is no need to touch any ball joints to replace/remove them.

Either way its straight forward swap. You will need a spring compressor, and an air gun will help as the top nut can be a pain to remove without the aided torque. Other then that it’s very simple. If you need step by step let us know and we will help.

For new struts/shocks IMO I would go with Bilstein Sports for lowered heights or with the Touring's for stock ride height. Also might be a good idea to see if the strut bearings need replacing.

[Layne]

http://www.realoem.com/bmw/showparts...51&hg=31&fg=10

#1 is a STRUT and it normally lasts the life of the car. #2 is a SHOCK.

[320iBimmer]

Thanks Layne, the right 'shock' is leaking. I thought the 'strut' was all one part. The diagram you sent confirms all of this. So I guess my question is how does one replace the shock? Is a spring compressor still necessary?

Thanks again

[Layne]

Is a spring compressor still necessary?

Yes. After the spring is off, unscrew #3 and the shock pulls out.

[TheNeek]

I call it a STRUT INSERT. Those gland nuts are a PITA!

[blitzed310]

http://www.realoem.com/bmw/showparts...51&hg=31&fg=10

#1 is a STRUT and it normally lasts the life of the car. #2 is a SHOCK.

Bilstein calls it a strut. I stand by my original post, E21's take a front strut, not a shock. The object attached to #1 is called the strut housing.

I've been wrong before...

[Layne]

Well we're all wrong, it's actually a Stoßdämpfer.

[blitzed310]

Well we're all wrong, it's actually a Stoßdämpfer.

That means Shock Absorber.

After looking around seems like the entire unit would be called a strut. And the "shock" that goes into the strut housing is being referred to as a strut insert or strut rod. I have always heard of this, therefore referred to it as a strut.

http://www.monroe.com/tech_support/tec_struts.asp

http://en.wikipedia.org/wiki/Strut

http://en.wikipedia.org/wiki/MacPherson_strut

[fullswing]

Yes. After the spring is off, unscrew #3 and the shock pulls out.

well, not exactly... there's that threaded ring that keeps the strut in the housing... you'll need some penetrating oil to loosen that up and potentially a pipe wrench. if you get new struts (bilstein sports are highly recommended), they will come with new brass rings.

here are some photos: LINK

let me know if you need any help.

[Jester323]

The gland nut that holds the strut cartridge into the strut assembly (the terms I've always been familiar with) is definately the toughest part. You will want to find a tool called an adjustable pin wrench like this one I've used various methods in the past to remove this gland nut, such as a pnuematic impact hammer with a chevron shaped chisel bit. This method usually works well, but about 20% of the time it will shear the spot welds that keep the top plate attached to the threaded part of the nut.

In the past when I have done this project & am just replacing springs/strut cartridges, I don't remove the ball joints. Just compress the springs with spring compressors, Harbor Freight sells them & Schucks rents them, and then use an impact wrench to remove the top nut that keeps the strut assembly to the upper strut bearing. CJ is right, it's next to impossible to remove/install this nut without an impact wrench & you may still end up needing to reach through the coils of the spring and hold on to the top of the strut cartridge to prevent it from spinning, a strap-wrench comes in handy here if that is the case. Then you will need to compress the strut cartridge as much as you can and push it out from under the fender. place a folded up towell over the top of the strut to prevent scratching the fender. You will need to use some force when doing this, although it's fairly easy if the cartridge is completely blown.

Once it is out from under the fender, easy on the brake line by the way, you will want to remove the small (8mm?) nut & bolt that attaches the brake line to the strut assembly to give you a little more slack, then simply slide the upper spring cup off of the spring (don't lose the washer that goes between the spring cup & the strut bearing) and pull the spring off. Then you can access the gland nut. You will want to shoot the gland nut with PB Blaster the night before, or at least a few hours before you do this so that it has time to soak in. Once the gland nut is off, the cartridge just pulls straight out. suck out all of the old oil & put about 1/4 pint of auto-tranny fluid, or some other type of oil, doesn't really matter, just acts as a coolant, down the tube & reinstall in the reverse order. Don't forget the washer that goes between the spring cup and the strut bearing or you will get a clunking sound over bumps... been there, done that.

One of the main reasons I like Bilsteins, other than the ride, is that they have a much better gland nut that is machined from brass and won't tend to seperate like the OEM nuts will.

Hope this helps.

[fullswing]

jester - would you mind adding a little bit more detail, like when i should inhale and exhale while doing all of that? but seriously, you are DA MAN.

320ibimmer - it was jester who helped me out when i had the same issues as you. he can't help being helpful in this regard...

[Jester323]

jester - would you mind adding a little bit more detail, like when i should inhale and exhale while doing all of that? but seriously, you are DA MAN.

320ibimmer - it was jester who helped me out when i had the same issues as you. he can't help being helpful in this regard...

Isn't that what tech forums are supposed to be about?

You give me too much credit. I'm just a shadetree monkey wrench like most of you. I've just swapped out my suspension a couple of times & then all the local guys dubbed me the local e21 suspension guru, so I've ended up doing all of theirs as well. All in all, I've probably only swapped out E21 suspension about a dozon times, all within the past 4-5 years, so it's still fairly fresh in my memory. That's all.

[TheNeek]

There have been many a swear words directed at gland nuts.

[Layne]

well, not exactly... there's that threaded ring that keeps the strut in the housing...

Thats why I said "unscrew #3", in reference to this drawing. http://www.realoem.com/bmw/showparts...51&hg=31&fg=10
Geez people, pay attention. It's as if you aren't thoroughly exploring every link posted or something.


P.S. Never ever use an impact wrench to put those top nuts back on the shock rod. The torque spec is surpringly low, the ends snap off easily, and that is not covered by any warranty.

[blitzed310]

There have been many a swear words directed at gland nuts.

My gf swears at my nuts all the time, huh

[fullswing]

Thats why I said "unscrew #3", in reference to this drawing. http://www.realoem.com/bmw/showparts...51&hg=31&fg=10
Geez people, pay attention. It's as if you aren't thoroughly exploring every link posted or something.


P.S. Never ever use an impact wrench to put those top nuts back on the shock rod. The torque spec is surpringly low, the ends snap off easily, and that is not covered by any warranty.

duh me... sorry about that buddy...

and about the PS., i DID use an impact wrench to put the top nuts... AND PROMPTLY SNAPPED OFF THE END of the strut. needless to say, i needed to get a new one - rather 2 new ones for matching purposes. good thing the one i broke was on a "previously owned" set. i have since been embarrassed to recount that episode until now.

[Jester323]

Thats why I said "unscrew #3", in reference to this drawing. http://www.realoem.com/bmw/showparts...51&hg=31&fg=10
Geez people, pay attention. It's as if you aren't thoroughly exploring every link posted or something.


P.S. Never ever use an impact wrench to put those top nuts back on the shock rod. The torque spec is surpringly low, the ends snap off easily, and that is not covered by any warranty.

Ahhh, if only it were as simple as "unscrew # 3"

Yeah, ya know, I've never had that problem of snapping the end off, & I had never heard of it happening until Fullswing told me that happened to him several months back. I have always seemed to have the problem of holding the shaft and keeping it from spinning inside of the strut cartridge when either removing or installing the top nut. Then again, I've also never installed a brand spankin' new set of Bili's either, I have installed brand new Koni Red's though & had the same problem of keeping it from spinning, which is why I've always used the impact wrench to remove & install. After hearing what happened to Fullswing & now this, I will be sure to use more caution in the future. Layne, do you happen to know what that torque spec is off hand? That would be a good bit of info for me to have in my pocket.

[Layne]

I don't have the exact spec, but I believe its around 30 ft.lbs (very little). I have a tool I made to do this with. It's a cut off deep socket with a handle welded on, and a second tool to reach through the socket and hold the rod. You could make one easy. I would consider loaning mine out, but I need to make a different holder since my new bilsteins have a different top (hex) than my bilstein tourings (two flats).

BTW, I once used a 24" pipe wrench on the gland nut. It worked fine without too much damage. If you have new nuts, even better.

[fullswing]

i'm not layne, obviously...
BUT the factory manual says 58-64 ft. lbs or 78-86 Nm

[Dave1965]

The gland nut that holds the strut cartridge into the strut assembly (the terms I've always been familiar with) is definately the toughest part. You will want to find a tool called an adjustable pin wrench like this one I've used various methods in the past to remove this gland nut, such as a pnuematic impact hammer with a chevron shaped chisel bit. This method usually works well, but about 20% of the time it will shear the spot welds that keep the top plate attached to the threaded part of the nut.

In the past when I have done this project & am just replacing springs/strut cartridges, I don't remove the ball joints. Just compress the springs with spring compressors, Harbor Freight sells them & Schucks rents them, and then use an impact wrench to remove the top nut that keeps the strut assembly to the upper strut bearing. CJ is right, it's next to impossible to remove/install this nut without an impact wrench & you may still end up needing to reach through the coils of the spring and hold on to the top of the strut cartridge to prevent it from spinning, a strap-wrench comes in handy here if that is the case. Then you will need to compress the strut cartridge as much as you can and push it out from under the fender. place a folded up towell over the top of the strut to prevent scratching the fender. You will need to use some force when doing this, although it's fairly easy if the cartridge is completely blown.

Once it is out from under the fender, easy on the brake line by the way, you will want to remove the small (8mm?) nut & bolt that attaches the brake line to the strut assembly to give you a little more slack, then simply slide the upper spring cup off of the spring (don't lose the washer that goes between the spring cup & the strut bearing) and pull the spring off. Then you can access the gland nut. You will want to shoot the gland nut with PB Blaster the night before, or at least a few hours before you do this so that it has time to soak in. Once the gland nut is off, the cartridge just pulls straight out. suck out all of the old oil & put about 1/4 pint of auto-tranny fluid, or some other type of oil, doesn't really matter, just acts as a coolant, down the tube & reinstall in the reverse order. Don't forget the washer that goes between the spring cup and the strut bearing or you will get a clunking sound over bumps... been there, done that.

One of the main reasons I like Bilsteins, other than the ride, is that they have a much better gland nut that is machined from brass and won't tend to seperate like the OEM nuts will.

Hope this helps.

Really, really interesting post. I just have one more question:

1) Do the bolts for the lower control arm and swaybar have to be removed?

[Jester323]

Really, really interesting post. I just have one more question:

1) Do the bolts for the lower control arm and swaybar have to be removed?

No, they don't have to be removed. I usually leave the control arm and sway bar attached to both the body & the strut assembly. But if you have a pnumatic impact hammer and a pointed impact bit, the removal of the ball joints is usually pretty easy. But that reminds me of something I forgot to mention before, but is pretty obvious once you get started, you'll want to detach the brake line bracket from the strut tube to prevent undue stress on it. If you do decide to completely remove the strut assembly from the control arm, you'll probably want to not only unhook that brake line bracket but also unbolt the brake caliper as well so that it can be completely removed from the car. Which is part of the reason I usually don't futz with that and just force the top of the strut cartridge/shock under the fender to remove the spring & shock.

[Dave1965]

No, they don't have to be removed. I usually leave the control arm and sway bar attached to both the body & the strut assembly. But if you have a pnumatic impact hammer and a pointed impact bit, the removal of the ball joints is usually pretty easy. But that reminds me of something I forgot to mention before, but is pretty obvious once you get started, you'll want to detach the brake line bracket from the strut tube to prevent undue stress on it. If you do decide to completely remove the strut assembly from the control arm, you'll probably want to not only unhook that brake line bracket but also unbolt the brake caliper as well so that it can be completely removed from the car. Which is part of the reason I usually don't futz with that and just force the top of the strut cartridge/shock under the fender to remove the spring & shock.

Agreed. Installed are one of the last sets of Fred's urethane-bushed control arms that I'd hate to mess the balljoints up on.

I'm going to keep as much attached as possible.

Thanks!

[goinstrong]

This thread was very helpful, and saved me taking everything apart like the Haynes manual suggests. The top nut on the strut released fairly easily, but the "gland nut" is a HUGE PITA!!!! Thanks for the link for the tool...I decided to forgo the grief and buy the tool. Thanks again!
I am putting H&R springs and the Sachs/Boge Turbo Gas struts/shocks on...
Tim