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Roof oil leaks & grades

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belljul
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Roof oil leaks & grades

Post by belljul » Sun Sep 29, 2019 8:10 pm

My e89 roof motor is leaking.

I found the problem (a burst O-ring seal in one of the brass hex screws on top) - see next post.

But when it comes to what oil to use...
I was using Carlube Jack Oil (SAE 10w ISO 32) (as some Z4 have recommended) and here's Halford's version, but Halfords said I shouldn't be using it as it wasn't the right spec for what I was using it for (synthetic vs mineral?).
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The closest they had was this from Comma whose spec sheet says:
A special synthetic oil based hydraulic fluid for power steering, central hydraulic and suspension level control systems. Also suitable for certain stability and traction control systems, hydrostatically driven fans, generators and air conditioning units, control of convertible car top covers and central locking systems.
Suitable for certain: Audi, Seat, VW, Skoda, BMW, Opel/Vauxhall, Peugeot, Porsche, Mercedes, Mini, Rolls Royce, Bentley, Saab, Volvo, Deutz, Fendt, MAN vehicles requiring a fluid of this type.
Recommended by Comma for applications requiring: CHF11S* and CHF202*
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Interestingly, the CHF11S spec on the Comma stuff that Halfords suggested, Febi do (item 06162 Hydraulic Fluid for central hydraulic system) for BMW part number BMW 81 22 9 407 549 - so not sure that is the right one for the hydraulic roof.

Unconvinced, I went to BMW who printed off the correct part being M54.34.0.394.395, 1 litre, £28. They all seemed to say I needed ZHM oil (Halfords hadn't heard of it).

But I found this: from Meyle: Convertible Roof Hydraulic Fluid MEYLE 0140206400, 54340394395 for £9.35 (note the matching spec of the last number ending 395)... on ebay...
and a similar product on Amazon from febi bilstein 02615 Hydraulic Fluid for hydropneumatic suspension and level control system for £9.90 delivered. Colour: yellow; Volume: 1 litre; Weight: 0,93 kg.OE numbers (for comparison purposes only): BMW 54 34 0 394 395; Mercedes Benz PKW 000989 910310
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I couldn't find anything on what is so special about ZHM oil was but this post proved interesting on a Saab convertible oil post. It mentions the difference in viscosity of the oils, not to use "cheap Jack oil", additives that destroy seals or pumps. He talks about using the Febi 02615 (mentioned above) identical stuff as ZHM/BMW part above.

So... I'm going to drain whatever is in my system now, top up with Febi 02615 (=ZHM/BMW M54.34.0.394.395) when it arrives and hope the leaks stop. Otherwise, it's a new motor... urgh!

Hope that helped!

LHM vs ZHM

Folks,

I believe that LHM used in other hydraulic tops is just fine, whether it's matching the OEM spec or not. I will quote some p/n's below that other brands are using. The seals in the cylinders will be okay with LHM, and the pump and valves shouldn't have any problems with it. Please don't go ultra-cheap with fluids like bottle jack oil, or you may get additives in the fluid that are not good for your system.

LHM and ZHM have different viscosities, but they are both acceptable for '99-'02 models, in my opinion. Neither one will damage the cylinders, and either one is acceptable for the pump. A thicker oil will pump a bit slower, but your cylinders actually have above average sized connectors and hoses. Thus, friction from a thicker oil isn't too much of an issue. A thinner oil might unveil leaks a little faster, but you're stuck having to get the cylinders rebuilt once you find leaks, anyway.

Here is what I have posted last week in response to another thread:

Mercedes approves a fairly inexpensive fluid that is clear in color: FeBi 02615. You can get it online for some $11/quart. Try autohausaz, for example, and enter "02615" in their search box. I don't see any reason not to use it on Saab systems; it is approved as top hydraulic fluid in MB convertibles from '90 to present. As a matter of fact, I recommend the same fluid to owners of BMW, Audi, VW, Bentley, Porsche, and others. The late 90's Saab convertible hydraulic system is quite similar to that of the Mercedes CLK series. Mercedes' own fluid is p/n 0009899103, and it has a green dye in it. In Australia and Asia, it is distributed under the brand name Meyle with the same part number, I believe. Mercedes also uses fluids with a red dye in it, but I'd like to keep this response fairly simple.

The Mercedes convertible top fluid is actually a "ZHM" fluid, as opposed to an "LHM". Frankly, I think that an LHM would be okay for Saab systems up to '02. Starting with model year '03, there have been some seals used that are extremely sensitive to additives in the fluid, and I would very highly recommend to use the FeBi 02615 or MB fluid for those.

I have heard that a long time ago, Mercedes actually took a Citroen fluid off their list of approved fluids because they found that the dye in the Citroen fluid affected the seals. That is hearsay as far as I'm concerned for now, and Citroen fluid may well be okay for MB systems again. Fact is, almost all car manufacturers use the same suppliers for their convertible top cylinders...

As far as brake system or self leveling suspension fluid is concerned, there is certainly some overlap. DO NOT USE REGULAR BRAKE FLUID IN YOUR TOP SYSTEM, EVER! Mercedes used FeBi 02615 in their self leveling systems through '02 (at least in the SL-Series, that is).

The important attributes for the hydraulic fluid in most top systems are the following: fairly even viscosity (thickness) over a wide temperature range, no additives that would harm your system (especially pump and valve seals in this case), and no emulsifiers that would suspend water in the fluid (you want any water to sink to the bottom of the reservoir).

A few remarks about using the wrong fluids or additives:

Unfortunately, "Stop-Leak" type products won't do any good on a Saab convertible system. Stop-Leak is designed to make certain seal materials swell up and thus seal cracks that have developed in the system. The seals in late 90's Saabs do not react to Stop-Leak; they are inert to it. However, once your seals are leaking, there is nothing you can do about it. On the down side, we have seen additives destroy hydraulic pumps, and that is an expensive loss for you. If the additive seems to have worked before for any of you, then it was likely the result of some other particles having temporarily clogged a crack in a seal.

Using much thicker (more viscous) fluid might slow down the leaks, but it will ultimately kill the pump and it will slow down your system. If your cylinders are leaking, then you need to get them rebuilt. (Or spend the extra bucks and buy new ones which will develop the same problem again in time - proper rebuilds will last longer than new OEM cylinders on account of better seal material being used...)

Here are some more OEM part numbers from other car brands; they should basically all be okay for convertible models up to '02

belljul
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Roof oil leaks & grades

Post by belljul » Sun Sep 29, 2019 8:13 pm

Update. Lifted the motor out, opened the ski hatch, ran the motor and with the help of a torch and some kitchen roll, identified the leak.
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It was a bust O-ring from one of the screws on the top.
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As a temporary measure, wrapped it in PTFE and bingo! It held.
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Ordered a set on Amazon - coming tomorrow.
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Total cost = £6.99 + £10 for new fluid.

Happy days!

flybobbie
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Roof oil leaks & grades

Post by flybobbie » Sun Sep 29, 2019 8:28 pm

Question is how did the o ring get damaged.
Or was it just leaking but snapped on extraction.

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RobbiZ4
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Roof oil leaks & grades

Post by RobbiZ4 » Thu Dec 05, 2019 11:41 am

:(
Last edited by RobbiZ4 on Sat May 23, 2020 9:47 am, edited 1 time in total.
Pardon, je suis Allemand :oops:
:ant:
E89 Roof Maintenance
viewtopic.php?t=130932

Y3 Roof Diagnostic System
viewtopic.php?f=23&t=129048
Image

flybobbie
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Roof oil leaks & grades

Post by flybobbie » Sun Dec 08, 2019 8:41 pm

Well screwing back in with the teflon probably a good fix and forget the o ring.
Like to know if that was the long term fix.

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RobbiZ4
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Roof oil leaks & grades

Post by RobbiZ4 » Sun Dec 08, 2019 9:01 pm

:(
Pardon, je suis Allemand :oops:
:ant:
E89 Roof Maintenance
viewtopic.php?t=130932

Y3 Roof Diagnostic System
viewtopic.php?f=23&t=129048
Image

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