Soft Top Hydraulic Motor Corrosion Due to Poor Design and Drainage in pump housing on BMW Z4

Problem Data
Average mileage: 65,058 (15,000–116,753)
5 model years affected: 2003, 2005, 2006, 2007, more2008
22 people reported this problem
Viewing 1 - 14 of 14 comments
William Searfus
1780 Indian Wy
Oakland, CA 94611

BMW of North America
RE: Z4 Soft Top Hydraulic Pump Corrosion
VIN: 4USBU33576LW66425
I love convertibles and have since the first one I saw in the 60s growing up in Southern California on the beach in San Diego…wow!
I have owned a convertible for most of my adult life driving one just about every day.
I bought the beautiful BMW Z4 in 2006 from Stevens Creek BMW in Santa Clara because they had what I wanted and worked a good deal with me and since I was working in Santa Clara I had all the service done in Stevens Creek. I live about 50 miles north however, in Oakland.
I loved this car and drove it to work every day from the Oakland hills where I have a home to Silicon Valley and from Santa Ana to work when I was in Orange Cty for about a year on a major project. What a great car for California. What a great car to commute in every day.
In July 2009 an idiot light went off and my top started to act weird when retracting. It actually got stuck in the down position thankfully but it was JULY for god’s sake, I could leave it down. However, I took it in to the nearest dealer to me, Weatherford, with whom I had shopped for a new car and visited the parts dept and that was about it. I bought the Z4 in Santa Clara because they had what I wanted and worked a good deal with me (and since I was working in Santa Clara I had all the service done in Stevens Creek). Since I lived up the hill from Berkeley, Weatherford was the place to take it when the top stopped working that day.
They told me at Weatherford that there was an electrical problem and they needed to remove my top and replace a harness. Unfortunately the harness was in Germany and they couldn’t put the top back on without this harness.
Brian, the service guy and Sherry Lee were both very helpful. They gave me a loaner and 10 days later I got my Z4 back. It worked great and I left. I thought it was weird that it took so long, but the explanation was plausible. I have worked in supply chain management for more than 30 years and I understand material constraints. (I also audit factories all over the world for a living, so I completely understand manufacturing). Weatherford Service Manager insists his shop would never had left off screws, and stripped any bolts. I have no proof, yet the service invoice clearly shows they had to remove the top to replace the harness. I know I wasn’t down in there. I can’t even replace the damn headlamps myself.
Fast forward to January 2012. My top stopped working one day at work when the winter weather was fabulous and I decided to take the top down. It started to open but never fully retracted. In reversing the switch I could get it to re-latch. I repeated the process to confirm what was happening. It would disengage, but not retract and I could always get the latching mechanism to re-couple, hmmmm. Not an electrical problem.
I took it to you at Stevens Creek to examine. You confirmed the hydraulic pump/motor was bad.
Okay – I did some research on this issue and it appears a well know design flaw. Look at the discussions about this on Bimmer Forums and Z4 forums on the web. And you tell me to keep pine needles out of my car and not let water get on it – sheesh…I understand to protect it, but what about car-washes? Does it get clogged in car washes? Do the chemicals in car washes corrode the pump inside this “housing”? It appears from the picture you provided me that the thing is
I have an extended maintenance plan on this car – did your service technicians ever bring this to my attention? Is it clearly documented in the manual to keep this area clean? Is it specific enough to make sure I keep pine needles out? Sheesh, I live in a forest.
Here is the compartment or enclosure that this pump sits in. Supposedly there is a drain down there someplace…the bolt seen in the left side of the picture is what is corroded and it sits 6 – 8 inches above the bottom of the enclosure, indicating that the water level in this “compartment” was consistently at the level of this bolt, causing it to rust and this is the reason for the welding – to remove this rusted bolt.

And then you tell me I have someone down in there stripping bolts? And leaving screws out and now my car is in the BODY SHOP being pulled apart or something?
NO ONE at BMW claims any responsibility for this, yet I only have the car serviced by you and Weatherford (and the dealer in Santa Ana, California when I was living there for one year – however they only replaced the brakes and that was it!)….
Could it be that this corrosion is the real root cause? Is this locking the bolt down that was stripped by an authorized BMW technician and now you want me to pay for his mishandling of this?
Look at this picture from the job- this is what was removed from the “housing” and the resulting corrosion. (Brian Phillips Email - BMW Service – Stevens Creek BMW)

I deal with FMEA (Failure Mode and Effects Analysis) and RCCA (Root Cause Corrective Action) as a part of my job every day in the high-tech manufacturing environment and if a customer brought this to my attention I would be FLOORED.
The last thing I would do was to blame the customer for something that my company designed so poorly and could compromise the integrity of both my product AND my world-class reputation.
At this point I am seeking advice on how to arbitrate this issue with my Insurance Company, USAA, the California Consumer Protection Agency, and the National Highway Traffic Safety Administration, BMW Consumer Affairs, my own personal attorney and others to seek a fair and reasonable resolution of this issue.
I would like to ask a BMW REGIONAL SERVICE person help me to arbitrate this issue as well and would appreciate your service department manager putting me in touch with this person immediately.
MISSING SCREWS & STRIPPED BOLT – (Brian Phillips Email - BMW Service – Stevens Creek BMW)

And all of this is happening because my top wouldn’t go down? Seriously? Chassis work? Seriously? Welding? Seriously? Like with a blow torch? Seriously?
QUOTED from SC BMW Service Coordinator, Brian Philips (2-7-2012), below:
They don’t want to cut through any reinforcements.
They are going to have to release the panels from all the spot welds then re-weld it.
The job is now being quoted at a higher cost. See below.
Now – why is all this work necessary….is this under warranty? Just to remove a stripped bolt?

On Feb 8th I personally visited AutoWest and met with the General Manager Sam Amini about the work he quoted here and to review the qualifications of the shop. I was told this was a BMW Certified Repair facility and I was shown the proposed work. I agree this is a terrible design and extremely prone to flooding because the pump sits in a plastic housing with a pin-hole drain at the bottom that is easily clogged. There is no overflow control and I can see that the enclosure probably constantly collects water and debris and soap, etc. Apparently this also causes the leaks I occasionally experience in the trunk and I now understand why my trunk gets wet.
Here is what he needed to do to access this damn bolt….

Bad design. Not very serviceable either. What happens in two years when the pump fails again?
On Feb 14th I was advised that there was a piece of hardware or this “bolt” that was supposedly shown in the microfiche parts catalog, but was not actually available from Germany – or was “backordered”. The local BMW service rep is suggesting that the body shop go and buy their own piece of hardware to weld into the chassis of my car so they can finish the job.
My concern here is now we are replacing body parts not from the factory to fix a problem that is caused by the poor design and I question whether this “solution” is sustainable and a quality solution that BMW will stand behind for the life of the automobile.
I was notified on Feb 16th that the bolt for the repair was a “BMW Replacement Part” and came in a box from the BMW factory. At this point the body shop is finishing their work and sending the car back to the dealer for repairing the soft top.
On Friday, Feb 17th, I am still awaiting confirmation on the car being moved from AutoWest back to Stevens Creek BMW to complete the repairs.
Hopefully all the parts are there at the BMW service facility.
On February 24th I finally picked up the car. The Service invoice was $3000
On March 1st I returned the vehicle for inspection since the work seems to be insufficient on the repair.
The harness replacement is causing a persistent “squeak” in my left ear now and the top “hammers” down when lifted and does not “glide” into place as it used to. I am returning the vehicle ONCE AGAIN for rework on March 7th.

From: Bill Searfus <>
To: Phillips Brian <>; Fuller Scott
Sent: Wednesday, March 7, 2012 7:57 AM
Subject: Received Your Voicemail about the Z4 Soft Top Repair Continuing Issues

Hi Brian,

I got your voicemail about the "bulletin" about some elastic straps that you now want me to
replace and I am a bit shocked again, sorry.

Can you please give me a copy of this bulletin? I would like to have a copy for review.

Can you please give me in writing, a statement that says this issue is NOT related to the work
you did before. I want implicit words from Stevens Creek BMW that you feel this issue was not
introduced during the repair of my vehicle at your service facility.

Can you please give me any MORE bulletins I should know about on 2006 Z4? I want to know
if there are OTHER issues you have not notified me about - or other of these bulletins that maybe
we should fix now as well?

This seems like an attempt to just get me to give you more money. Why did this come up now?
Just because of the repair and now the damn thing slams?

Does this add value to the car? I need to read the bulletin to understand WHY I should pay you
now to do this work - it may not be worth it.

Have you found the squeaks in the top? You did NOT EVEN MENTION the squeaks in your
voicemail, you just asked me to give you more money - sheesh!

Holy cow! Can you just repair the squeaks so I don't hear the lousy workmanship your tech left
in my repair I just paid $3000 bucks? What is up with THAT?

Sorry - I am very patient but I am also very frustrated with all of this. I now question whether I
should even trust the BMW brand. I was going to buy another Z4, but I am having second
thoughts now. When Scott told me he has a Viper - that concerned me. I am thinking about a
Viper or something, but I question that BMW is the way to go for me in the future based on my
service experience on the Z4 (not Steven's Creek, per se, but BMW...)

Brian - I am not taking this personally, you are doing a fine job - but you have to understand my
royal frustration with this mess.

PLEASE CALL ME AT 510-219-7733.



Bill Searfus
Bill Searfus //s//
William Searfus & John Jensen – Co-Owners/Co-Insured
VIN: 4USBU33576LW66425
1780 Indian Wy
Oakland, CA 94611
Top will not raise. Motor runs but nothing happens. Cannot pull lever or turn handles to manually close top.
Top won't go down or up. Motor running but nothing happens. Lot of noise coming from the motor.
My convertible roof motor has failed three times in my 2006 Z4, and twice in the older Z4 I had on lease before. Fortunately, all the failures (so far) have occurred during warranty. The BMW service guy told me it is a known poor design that is causing the failures. He said rain water actually drains through the compartment where the ELECTRIC motor is housed. The drain holes get plugged with leaf debris, etc so the water builds up and fries the motor. I'm not an engineer, but it sure sounds like a pretty absurd design to me.

The service guy told me it would have been about $1,400 if I had to pay for the repair (each time). I'm sure it will fail again some day and my car will then be a coupe instead of a convertible. In the meantime, I will try to put off the inevitable by keeping the car in the garage when the trees are dropping debris and when it is going to rain...

I guess it's more of an indoor car ?
Top has 2 motors, lock motor and motor for hydraulics. Lock motor is fine, but the one for the hydraulics just hums. BMW dealer quoted $1,800.00 to fix it. Found a motor for $350.00 at a euro-salvage, but the job will be labor intensive. Will need a partner for help in lifting the retracted top out. Tons of youtube videos out there for step by step help.
Convertible top would not go down. Issue caused by clogged drains causing motor to sit in standing water. Replaced top motor. $1100.00
2004 with less than 30k convertible top motor died. 2008 with less than 50K convertible top motor died.
Obviously they have no intention of making a simple redesign.
Push button Rag top would not go down.
Motor rust out
Motor encased in sound "proof" material without a drain!
Over the years of washing water remained in and around motor; hence a block of rust was found! Extremely poor design. This should be classified as a recall! My out of pocket expense so far is one thousand two hundred ninety seven dollars and it is still in the repair shop for this reason only!
Top disengages but only about 1/4 inch. Will close and lock. It has not been fixed. Told by dealer that the fix would cost $1,750.00.