Monday 1 April 2013

Soft top hydraulic motor replacement

In September my hydraulic motor for my power roof stopped working. I soon found out that this was due to water ingress in the motor housing due to blocked drainage hole......weak huh?
A replacement motor was a cool £350, plus a new housing and hydraulic repair kit, bringing the total to £450. Replacing the motor involves removing the entire roof assembly which is a fiddly and laborious job and is an expensive option if you are going to get this done at an Indy garage.

I decided to attempt this myself & with the help of my girlfriends father I managed to get it done this Easter weekend.


First there was a lot of trim to remove, mainly from behind the seat to gain access to the roof electrics. I also had to remove the luggage expansion shelf from the boot. This shelf moves up and down to make space in the boot but it has to be down to allow the roof to be stowed. I soon discovered that there is a micro switch that is flipped to disengage the roof cycle if the shelf is up. This I overrode by jamming a socket in the channel ;)


My Z doesn't have the upgraded subs so I removed the storage unit from behind the passenger seat and the air vent cover on the right. This makes it easier to get to the roof control module and the 4 different electrical connections.

The white box is the roof control module. Next to it is a plug that covers access to the roof bolts.


Unfortunately my drivers seat won't move forward due to a faulty motor so I had to tilt the seat forward to gain access to the air vent. The storage unit didn't have to be removed this side as there are only 2 electircal connections on the drivers side.


With the bowden cable engaged I was able to move the roof manually to allow some slack so I could then remove the seal from the body work.


Seal removed. The corners were a NIGHTMARE.


Roof off and placed on the lawn :) We figured out after a few attempts that the roof needed to be half up to slide the rear loop from the body work. The loop that I speak of is an aluminium bar that bolts onto the bodywork and keeps the fabric taught and improves security. This was attached to the car by a series of bolts and 2 horrendous clips that were just completely unnecessary.


Picture of the car with the roof removed. Naomi's dad Jeff, my trusty assistant for the day :)
You'll notice the masking tape all over the wing of the car, this saves damaging the paintwork when removing and replacing the roof. That and you spend most of the time leaning up against the car. I worse trousers with no metal zip or buttons but its better to be safe.



So these where the wells in which the roof mechanics sit. These are also water drains for run off from the roof. There is a hole at the bottom that you can see is gunked up. This caused the water to pool and swamp the motor. Not exactly the best design ever.


Drivers side was even worse. Still a lot of water trapped in this one.


This is the roof motor encased in its housing. The cables running out are the hydraulic lines.


Now the pump removed from the housing. No wonder it stopped working :/


The pump next to the new one. Shiny.


Unfortunately the vinyl had split on the drivers side of the roof. This is under the visual line of the roof and hidden in the recess but was probably causing more water to collect in the well. Jeff used a combination of hot glue and some serious gaffer tape to seal this back up. This kept it flexible and did a great job to repair the damage.


I spent the next 2 hours cleaning all the parts of the car that would need reassembling. The wells were cleaned out and the holes unblocked. I used a length of washing line to run all the way down to the drainage outlet in the wheel arch to make sure it was clear and then flushed it though with a few litres of water.


Clean and water free.


You can see the damage the water has also caused to the hydraulic ram. My one bad was that I forgot to treat the rust on this part :S I hope this holds out in the future.


The hydraulic lines connected to the new pump and the bowden cable assembly connected to the unit. This was a bit of a pain as it seemed to stick a lot and I was concerned it would be stuck on when I sealed the unit inside the housing and dropped it back inside the car :/
Thankfully this wasn't a problem. I used so motor oil to run down the cable and freed it up a bit.

The lines needed new washers and new bolts and the switch over had to be fast as to lose as little hydraulic fluid as possible.

The new unit is actually flipped in comparison to the original. This was very confusing and I spent a lot of time reading up online to find out which was the lines should be connected. I decided to go with the labeling on the new unit which meant reversing the lines and the electrical connections.

I was correct in my decision :D


The new unit in the new dry housing and bolted onto the roof assembly.


Need to dispose of a body? The boot is certainly big enough ;)
Jeff reconnects the bolts that hold the hoop to the bodywork.

The roof was dropped back in. This sounds simple but was in fact the hardest part of the job. Again the roof needed to be half up to get the alignment right.


Some silicon grease on the seals and a lot of pushing and the roof was back on.

We started this job at 8.30 and worked through til 6. Amazingly the roof worked first time without any priming. Then refit the trim and our man work is done :D

Roll on summer.

19 comments:

  1. Yo I saw a bear image you made a while ago and was wondering if I can maybe use it for a poster idea (nonprofitable) PLEASE GET BACK AT ME THANKS! :)))

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  2. I have the same problem with mine and too scared to attempt this on my own, if i pick up all the parts, how much will you charge to give up some time of your weekend along with me being the helping hand?? i really don't want to go to the dealer with this problem. jay:))

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    Replies
    1. Jeff, I have the same problem, do not feel brave enough to replace the mnotor on my own. No way I am going to BMW dealer though, they charge too much. would love to do it myself, are there any step by step instructions online in addition to whats here? thanks

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  3. Were did you find the new electric/hydraulic pump motor banjo bolts? I am finding it very hard to find them.

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  4. got one on ebay from a company in Bradford for 365

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  5. Hi, mine too. Found a guy in Hook, Hampshire who works for BMW. He rejuvenated the old flooded motor and re-sited it out of harms way in the boot. He charged £200 and completed the job in under 2 hours!! If you join the Z4 owners club, there are a few people there scattered around who can complete this task, usually without having to buy a new motor.

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  6. If you take the bolts out of the aluminum hoop first, the body seal is easier to remove

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  7. Great Blog , Interesting information on Hydraulic Motors

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  8. There’s no need to remove the roof, I removed the motor in 40 mins on mine. You have to persevere but once you remove the duck tape around the lid of the plastic housing you can pull the motor out into the boot compartment still connected.
    100% true.

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  9. Did you replace the motor and install the new one into the boot?

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  10. I am happy to find this post Very useful for me, as it contains lot of information. thanks HKS Rotary Actuators&Helical Rotary Actuator | Rotary Actuators Manufacturers

    ReplyDelete
  11. IF YOU KEPT THE NUMBER PLATE R1YNF PLS CONTACT ME

    ReplyDelete
  12. Hi Roch, I hope you pick this up as it was a couple of years ago since you making this post. Do you have contact details for this chap in Hook as I now have this issue. Thank you

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  13. Anyone have experience with eBay motors? I'm assuming there from China & should be avoided.

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  14. my motor went 10 years ago and it cost $1,300 at the bmw dealer. Fortunately it was under an extended warranty. It just went again and the dealer told me it would cost $5,000!!!!! HELP

    ReplyDelete
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