How to replace soft top motor without removing roof.. DONE!

[Ducklakeview]

Couple of things. Firstly, if the motor has failed due to water ingress, which is the case for 100% of the one's I have repaired, then IF you pull the bypass, there is a VERY high chance that either; It will not work, or that it will seize in the "bypassed" position. Reason for this is that the bypass cable operates a small brass plunger on the side of the pump, as the pump is alloy then you get galvanic or "different metals" corrosion between the two. Due to this, on every repair/relocation I do, I always remove the bypass actuator lever and physically check and free off the plunger. MOST of them are stuck, usually in the bypass position if the red ring has been pulled.

Secondly, I can pretty much guarantee that you WON'T need a new motor. They are sturdy little things, and respond well to a little TLC. I've NEVER had to replace one, even those that have been seized solid, and not worked for years can be brought back to full working order.

Mike

 

[Ducklakeview]

New member to z4 forum. Bought a 2008 z4 4 weeks ago, roof motor failed last week, made numerous enquiries to have said problem resolved. Quotes even from BMW independent in excess of £600 plus VAT, plus the doom and gloom story as to additional cost if hydraulic lines are faulty. Then, with a bit of searching, and the use of the Z4 Forum, came upon Mike in St Helens, rang him Monday, arranged to take car to him Tuesday 6.00pm, left 45 minutes later with roof in complete working order. This guy is the nicest person you will ever meet and a miracle worker, and I do not say that lightly. Do not entertain going to any independent or BMW direct just make contact with Mike and your roof problem will be resolved pretty well as soon as you can get to him.

Many thanks Mike - Was great to meet you!

Mike

 

[Hughesy99]

Mike, thanks so much. That is exactly what it was. Roof now fully operational!

 

[Marlon]

Mike, thanks so much. That is exactly what it was. Roof now fully operational!Stuck valve.jpg

Mike knows his stuff and is happy to share knowledge too

 

[NeilZ4E85]

Hi

I have a 2005 Z4 and it is not just a tie wrap around the body of the plastic bucket which the motor sit in holding the bucket place. It has a triangle piece of plastic coming of the body of the bucket with 2 slots in it, there was one tie wrap on it which I have removed but the bucket will not come out no matter how much I pull. Something else must be holding it even though you can wiggle it quite easily an it feels free. If I cannot free this plastic bucket with the motor in I will have to remove the whole roof.

Has anybody else got any suggestion on how they may have overcome this problem.

Thanks.

 

[ch_ryqmhho]

Guys, I need your help. I tried to follow the instructions and think I got the casing free....seems to be movable, but only straight upwards. But this is where the silver loop of the soft top is blocking the removal.

Any ideas? Am I missing something? Can the experts here let me know from the picture if the casing is in the right position? Or has it been messed with before and is unusually angled?

 

[Hughesy99]

Hi there, hard to tell for sure from the pic but it looks normal. It moves up and down vertically as there is a long slot in the casing that has a large cable tie through it. The slot has a weak point at the bottom which you have to break by force to free it from the cable tie. There is no easy way to do it other than to try and get the right leverage to snap bottom of the slot in the casing. It takes quite a bit of perseverance and is pretty frustrating. I found that if you can get you hand under the bottom of the casing and pull it towards the rear of the car while pushing the top of the casing towards the front it eventually gave. Not easy to do with so little room but stick with it.

 

[ch_ryqmhho]

Hughesy99, thanks for your reply. Are you saying that once the bottom of the slot is snapped off then I'll be able to move the casing laterally/horizontally and not only vertically?

 

[Hughesy99]

Hi,
Yes, once the slot breaks you will be able to lift the whole casing out of the well to the extent that the motor power cables and hydraulic lines will allow, it's just enough to get the assembly into the boot. If you can remove the tape that goes round the casing then you can remove the top of the casing and lift the assembly partially out of the lower casing which can help you get a bit more leverage on the lower casing. The power/hydraulic lines loop round and go under the lower housing so until you get that out movement is very limited.

 

[ch_ryqmhho]

OK, update. I finally managed to get the thing out. Had to pry open the top of the case, then I could take out the motor and then the rest of the case. The motor was disgusting. If it wasn't for Ducklakeview I would have ordered a new one right away but he mentioned that these things can be brought back to life. Took me forever to figure out how to open it and where to apply force, but then some cleaning worked wonders.
So I put the motor back in and topped off hydraulic fluid (lost some when I detached the motor) and it runs fine (as in fast). Unfortunately very little power seems to get to the top. I undid the bowden cable attachment on the motor to make sure that the override valve wasn't stuck but that doesn't seem to be the problem.

When I manually put the top in the half open position, I can slowly move it in both directions for a bit. It's like there is only a fraction of the needed pressure going to the hydraulic cylinders....almost like it's pumping air. I read that these assemblies are self-bleeding. Is that really the case in all situations?
The motor, while going fast, also sounds kind of hollow and a little rattling. But that might just be because it's now hanging loosely in my trunk without any sound protection. Is it possible that I did not attached the pump to the hydraulic head (?) correctly? I noticed a little metal pin fall out that I put back in when I put things back together.
Any help would be greatly appreciated. I've come so far, would be a shame if this didn't work out now.

 

[Ducklakeview]

OK, update. I finally managed to get the thing out. Had to pry open the top of the case, then I could take out the motor and then the rest of the case. The motor was disgusting. If it wasn't for Ducklakeview I would have ordered a new one right away but he mentioned that these things can be brought back to life. Took me forever to figure out how to open it and where to apply force, but then some cleaning worked wonders.
So I put the motor back in and topped off hydraulic fluid (lost some when I detached the motor) and it runs fine (as in fast). Unfortunately very little power seems to get to the top. I undid the bowden cable attachment on the motor to make sure that the override valve wasn't stuck but that doesn't seem to be the problem.

When I manually put the top in the half open position, I can slowly move it in both directions for a bit. It's like there is only a fraction of the needed pressure going to the hydraulic cylinders....almost like it's pumping air. I read that these assemblies are self-bleeding. Is that really the case in all situations?
The motor, while going fast, also sounds kind of hollow and a little rattling. But that might just be because it's now hanging loosely in my trunk without any sound protection. Is it possible that I did not attached the pump to the hydraulic head (?) correctly? I noticed a little metal pin fall out that I put back in when I put things back together.
Any help would be greatly appreciated. I've come so far, would be a shame if this didn't work out now.

Probably a seized bypass plunger, very common.

Mike

 

[ch_ryqmhho]

Mike, isn't that the piece that gets pushed in when the bowden cable is pulled? Seemed to me like the little thing is moving when I pushed it in with my fingertips. But then I don't know how much it is supposed to stick out. What would be the best way to "unseize" it?

 

[Ducklakeview]

Mike, isn't that the piece that gets pushed in when the bowden cable is pulled? Seemed to me like the little thing is moving when I pushed it in with my fingertips. But then I don't know how much it is supposed to stick out. What would be the best way to "unseize" it?

Yes, but it will still be seized, as the lever that operates it is loose in it's fixing anyway. Remove the three tiny screws from the black plastic cover, and you'll see a brass pin. THAT is the actual bypass, it should push in easily with your thumb and instantly pop all the way back out. It only travels about 2.5mm, but needs to come out as far as it's stop, otherwise the roof won't work. Soak it in release oil and get a pair of long nosed pliers on it, work it round and in and out until it's free. Just noticed that you said "a pin came out" was it a brass pin or a hardened steel one, a bit like a bearing roller?

Mike

 

[ch_ryqmhho]

Mike,

the little brass pin was moving pretty freely but I did put some lubricant on it and now it really seems to move pretty smoothly in and out. Situation is unchanged though. I can open the roof manually with zero resistance about 2 thirds of the way. Then sometimes I can push it harder an can hear a whirring from the hydraulic unit and can push it all the way back. Sometimes I encounter resistance that cannot be overcome. I can then press the opening button and the roof opens ever so slowly most of the way. The closing button never does anything. But I can then close the roof manually again without much resistance and start over. I don't seem to have a leak as I am not losing any hydraulic fluid. Still thinking that I might have lost a part when removing the motor or something. All I had was the little metal pin and the yellow plastic circle. Is there a diagram of the whole thing somewhere?

 

[ch_ryqmhho]

Here's a picture I found:


Is this little black rectangular piece critical? I don't remember seeing it.

 

[Ducklakeview]

Yes, that part is critical, without it the motor shaft will wear the plastic wheel quickly and drive to the pump will be lost. I know as I recently had to replace one for a forum member who hadn't realised it was missing.

Mike

 

[ch_ryqmhho]

Oh, so where does it go? does it go into the middle opening of the plastic disk?

 

[Ducklakeview]

Oh, so where does it go? does it go into the middle opening of the plastic disk?

There is a slot on the underside of the disc that it fits into.

Mike

 

[ch_ryqmhho]

Mike, thank you, found the part and figured it out in the meantime. Who would have thought that such a tiny piece of metal makes all the difference. Luckily the disc wasn't worn too badly yet and now the rattling has stopped and the pump is actually working!

Now the roof is (mostly) moving and I am experiencing a phenomenon that I noticed before the motor gave out in the first place: while the system can easily close the roof, it doesn't have enough "pull" to open it from the closed position. I need to help manually. Interestingly, a couple times I managed to move the roof back and forth a little bit several time and the pulling strength increased to the point that it could open by itself. After closing the roof again it was back to being too weak though.

Any ideas? I understand that this is not a motor issue anymore. I'm clueless though.

 

[Steveo1570]

Hi,
Just like to thank everyone who has contributed on this post, after weeks on and off trying finally managed to get the motor to the boot. I wasn't able to get the whole plastic casing out but managed to get the lid off by hooking it with the end of a bungee chord and ripping it off. Gained access to the casing from behind the passenger seat. So relieved as this is one of the most frustrating jobs I've ever attempted on the car!
I think the motor is terminal though, spins freely with fingers but no life when powered up. Have got it soaking in diesel now but not holding my breath.
One question though, should there be a spring on the steel pin inside the pump? I've heard others mention it but can't find it (pump did fall apart when I removed motor).