Front top mount, will it last...?

[Steve84N]

So I've discovered my front nearside top mount is split nearly half way around the top of the damper strut. I'm planning on fitting a full B12 kit with new mounts next Friday but do you think this mount will last another 200 miles or do I absolutely need to change it out tomorrow? I only ask for opinion as I haven't got the new suspension yet but I should have the top mount by tonight. I don't want to have to do the labour twice if I don't have to. It didn't move after I noticed it yesterday morning and a further 50 miles...

Would the damper go through the bonnet if it failed?

 

[srhutch]

Wonder how long it's been like that.

But no I wouldn't drive it.

 

[PboroRyan]

I'm not sure if it'll last, but in answer to your second question, yes it absolutely could leave a nice big hole in your bonnet if it does all give up - springs are under a lot of pressure, and if the shock and assembly can't go down, it'll go up instead. Not saying it will but it's very possible! :thumbsdown:

 

[Steve84N]

It's not been like it for long as I've only recently been under there adding more camber. Maybe that means it could deteriorate quickly...

My understanding is the spring would be fine as it sits against metal plates outside of the rubber area so it's just the damper rod that would fully extend upwards. The corner of the car wouldn't drop as it's the spring that holds it up. Therefore, it's just a question of how far the damper is already compressed at rest versus the space to the bonnet.

 

[Paulr]

I suspect as a Mcpherson strut, that the plastic lug is covering a bolt that goes through a small hole in the top of the inner wing. Below that the strut usually has a larger welded-on collar arrangement to hold the spring, which is also what those three bolts attach to, so it will not pop though that large hole you are looking at there.

That is the usual arrangment, I assume BMW are no different?

 

[Steve84N]

Yes, amended my last reply as such. Hence why I'm considering chancing it. :|

 

[Paulr]

Forgot to mention, I would not drive it until it is sorted as your steering and handling will be radically affected.

 

[PboroRyan]

From what I remember when I put the eibachs on, there is a collar underneath like the picture above that holds the spring. However, as this is hidden, you can't rely on the fact that it'll hold the assembly. Also, if the top of the mount looks like that, you have to assume the collar isn't in it's best state either. I wouldn't go very far or at any speed if I knew my top mount looks like that. To each his own however - it could last another 1000 miles, i'm not one to chance that sort of thing though.

 

[Steve84N]

The steering is fine, the handling seems OK too.

However, I hear what you guys are saying so probably best to switch it out just in case. Practice for next week I guess!

 

[PboroRyan]

Assuming you're not unfamiliar with a spanner, it's a pretty easy process, the hardest part is getting the seized bolts off, so it shouldn't take too long!

 

[Steve84N]

So long as the pinch bolt plays ball on the knuckle it should be alright. Not looking forward to using spring compressors for the first time though.

In retrospect this is actually quite a scary failure as it's gone from nothing noticeable to that in far less than a service interval!

 

[Ducklakeview]

It CAN'T pop up through the bonnet, the spring is held between the top and bottom spring seats, the top seat is secured by another nut, which is BELOW the rubber you can see, it's that bolt which holds the spring compressed when you remove the strut.

The damper rod, which is what the top central nut goes on, is not under spring pressure. EVEN IF the rubber falls to pieces, the worst that will happen is that it will become noisy and the steering will get vague with increased tyre wear. You've driven it like that for how long? Another 200 miles ain't gonna cause a problem!

Mike

 

[PboroRyan]

For me, compressing, dismantling, and re-assembling the shock was the longest part. I didn't have any problems with the pinch bolt on a 12 year old car, so you should be alright - a breaker bar is definitely handy though. Also make sure you have fairly short spring compressors, the coils are quite tight even on the standard springs, my spring compressors didn't really do the job properly if i'm honest and I had to improvise with ratchet straps (not the health and safety way to do it it i'm still here ).

 

[Steve84N]

I know the spring and strut can't pop through but the damper rod could then fully extend. Thinking about it that's probably enough to reach the bonnet as the wheel has a fair drop when you jack it up. That same distance would see the damper rod hitting the bonnet and the force would easily be enough to dent if not puncture.

Thanks for the tip Ryan, was looking at buying these tomorrow morning: http://www.halfords.com/workshop-tools/tools/hand-tools/laser-coil-spring-compressor

 

[PboroRyan]

No worries! They look like they're a bit smaller than mine so should be able to get round the tighter coils and compress more, but it's hard to tell from a the picture. I guess being Halfrauds you could return them easy enough if they're too big.

 

[Ducklakeview]

I know the spring and strut can't pop through but the damper rod could then fully extend. Thinking about it that's probably enough to reach the bonnet as the wheel has a fair drop when you jack it up. That same distance would see the damper rod hitting the bonnet and the force would easily be enough to dent if not puncture.

Thanks for the tip Ryan, was looking at buying these tomorrow morning: http://www.halfords.com/workshop-tools/tools/hand-tools/laser-coil-spring-compressor

The damper rod CANNOT extend, it's limited by the top spring seat! Even IF all of the rubber is gone, it may protrude 10-20mm further through the top mount, which is nowhere near enough for it to touch the bonnet, by which time it would be making one HELL of a racket!

Mike

 

[Steve84N]

Thanks Mike, in that case it can stew for another 200 miles.

 

[Yorkie Z]

I know the spring and strut can't pop through but the damper rod could then fully extend. Thinking about it that's probably enough to reach the bonnet as the wheel has a fair drop when you jack it up. That same distance would see the damper rod hitting the bonnet and the force would easily be enough to dent if not puncture.

Thanks for the tip Ryan, was looking at buying these tomorrow morning: http://www.halfords.com/workshop-tools/tools/hand-tools/laser-coil-spring-compressor

The damper rod CANNOT extend, it's limited by the top spring seat! Even IF all of the rubber is gone, it may protrude 10-20mm further through the top mount, which is nowhere near enough for it to touch the bonnet, by which time it would be making one HELL of a racket!

Mike

Exactly this. Wouldn't worry to much mate.

 

[ben g]

Should be OK, just don't go driving around like Lewis Hamilton :lol:

Regarding spring compressors, the standard type don't work (as another member has said) as they won't compress the spring enough.

I found this out the hard way, but luckily my dad's mate sorted them out.

The Halfords ones you posted look smaller, so should do the job. If you get them, check them out instore against a standard sized set if you can.

 

[Steve84N]

Will do.