Convertible top hydraulic pump

[Marvin]

Picture is of the hydraulic pump in the trunk. How do you add fluid in this hole in the center? 1998 Z3
Thanks Marvin

 

[t-tony]

Sorry I can't help right off Marvin, can you see that the fluid level is low through the clear container?

Tony.

 

[Marvin]

@t-tony there is no hydraulic fluid in the clear container. Didn't think hydraulic fluid would evaporate. My first thought is there could be a leak in the hose somewhere and then when I fill the container fluid could end up in the trunk or inside the interior. After taking the picture it's much more visible and an Allen wrench will open the center fastener and I will add the fluid. The Bentley Service Manual doesn't give enough information or I am not smart enough to figure it out. Will see what happens after work and I add the hydraulic fluid.
Appreciate your support.
Marvin

 

[t-tony]

Ok Marvin, please let me (us) know how you get on with this. Hope all goes well my friend.

Tony.

ps. I hope you don't find a leak.

 

[Marvin]

Added BMW'S approved fluid and all was working well last night. Placed several towels underneath the reservoir before calling it a night to catch any leaking fluid.

This morning the reservoir was empty about 8 ounces missing and the paper towels were dry. I now know the electronics work. Will keep trying until it's fixed.
Marvin

 

[t-tony]

Well then the mystery is where did the fluid go then Marvin. It's got to be fairly obvious when you do find it. Good luck!

Tony.

 

[Marvin]

Turns out to be a leak in the hydraulic hose or hoses attached to the cylinder piston behind the drivers left shoulder deep in a metal well. Soaked up the excessive fluid with a long stick and paper towels. But going to be a bear to fix. Seems odd the Bentley Service Manual makes no mention of the cylinder piston.

I'm a novice mechanic so will have to wait till I can take a few vacation days from work. It's my daily driver. Time to learn.
Marvin

 

[oldcarman]

@Marvin you can disconnect the cylinder from the hood and go manual to put it up and down. I don't have the hydraulics and it takes very little time to get the hood up ! HTH JIM

 

[pgunter]

@Marvin

Have you looked at these online.

http://www.realoem.com/bmw/enUS/showparts?id=CH71-EUR---Z3-BMW-Z3+1.9&diagId=54_0201

http://bmwfans.info/parts-catalog/Z...lding_top/electro_hydraulic_folding_top_parts

At least you can find the part and numbers.

 

[Brian H]

@Marvin you can disconnect the cylinder from the hood and go manual to put it up and down. I don't have the hydraulics and it takes very little time to get the hood up ! HTH JIM

You don't need to disconnect Jim, there is a relief screw on top of the pump, just unscrew this and you have a manual roof .

Edit, if you look at the pic in the first post you can just see the t shaped handle of the relief screw

 

[oldcarman]

You don't need to disconnect Jim, there is a relief screw on top of the pump, just unscrew this and you have a manual roof .

Edit, if you look at the pic in the first post you can just see the t shaped handle of the relief screw

I don't have an electric top @Brian H but was going from memory but thanks , that's even easier than unclipping the cylinder. Now I have two things to remember should this ever come up again! Shocked I even remembered one personally. JIM

 

[Brian4]

Hi @Marvin here is a bit of a write up from @spurs fan in a coupe about removing the cylinder.Looks as if some of the trim on the left hand side has to be removed to access the pin that holds the ram in.

https://zroadster.org/threads/remove-z3-auto-hood-roof-hydraulics-etc.3391/

 

[Marvin]

@t-tony @oldcarman @Brian4 @Brian H @pgunter @spurs fan in a coupe

Thanks for the information. Relived pressure at the tank and running manually. Top and cylinder piston work great until the fluid runs out. I can hear the fluid gurggerling in the line as I try to get the top up and the fluid runs out. Other than time shouldn't be too costly. Appreciate the links. Couldn't fix on my own without them.
Marvin

 

[oldcarman]

Lots of help around here @Marvin all you need do is ask!! Good luck. JIM

 

[marqueymarxc]

I also have a dilemma here. The reservoir seems low, and I would like to know how to fill and also with what. I'm in the US as a lot of what i've found are UK parts.
Secondly, the motor seems to stop of its own accord when the roof is about 1/4 of the way back up. The microswitch seems to be doing its job, as I can stop it earlier in the travel by engaging it manually.
Does the hydraulic pump turn itself off if the reservoir is too low?
Does anyone know what would cause the roof to operate only from totally down to 1/4 of the way up and then stop?

 

[GazHyde]

@marqueymarxc - which type of pump do you have? If it's the type below then the fluid level needs to be in the range of the white circle on the middle of the reservoir. I can't remember if that is when it's up or down, I suspect from memory it's that level when the roof is up. It would then be more full when the roof is down as the piston will be empty.

Not sure how to tell the level on the earlier pumps though!

 

[Marvin]

@marqueymarxc
My wife is at work and I'm locked out of the garage or I would post pictures.
I used a generic hydraulic fluid bought at O'Reillys and you will need a small 6 ounce or so oil can with a 4 or 5 inch long flexible hose to reach the fill hole in the fluid reservoir. Inside the hole is a metal rod. You will have to pump the fluid slowly as the metal rod will push out the fluid if you pump to fast. The pump works when you press the button on the console. If you can get the Z in an enclosed space and only turn the key enough to get the accessories to turn on then press the convertible top button with the top down you should be able to here the cylinder piston in your left ear.
Hope this helps.
Marvin

 

[Marvin]

@marqueymarxc
Forgot to say - the top is only supposed to go up 3/4 of the way. This is to allow you to open the locks on the side of the top. Your supposed to lower it by hand the last 1/4 of the way and then secure the locks.
Marvin

 

[FRANKIE]

@marqueymarxc
My wife is at work and I'm locked out of the garage or I would post pictures.
I used a generic hydraulic fluid bought at O'Reillys and you will need a small 6 ounce or so oil can with a 4 or 5 inch long flexible hose to reach the fill hole in the fluid reservoir. Inside the hole is a metal rod. You will have to pump the fluid slowly as the metal rod will push out the fluid if you pump to fast. The pump works when you press the button on the console. If you can get the Z in an enclosed space and only turn the key enough to get the accessories to turn on then press the convertible top button with the top down you should be able to here the cylinder piston in your left ear.
Hope this helps.
Marvin

I can only speak to you from once having a Mercedes slk which has a hydraulic hard top that folds into the trunk. The fluid that I had to use for this pump was not ordinary hydraulic fluid but much thinner. I cannot speak for what is used in the BMW. It was very expensive. Frankie

 

[FRANKIE]

@t-tony @oldcarman @Brian4 @Brian H @pgunter @spurs fan in a coupe

Thanks for the information. Relived pressure at the tank and running manually. Top and cylinder piston work great until the fluid runs out. I can hear the fluid gurggerling in the line as I try to get the top up and the fluid runs out. Other than time shouldn't be too costly. Appreciate the links. Couldn't fix on my own without them.
Marvin

I once had to rebuild a hydraulic piston for my top in a Mercedes but I don't know if you can do this for a BMW. However.....
http://www.tophydraulicsinc.com/en/51-rebuild-upgrade-service-for-96-02-bmw-e36-z3-top-cylinder