Roof Microswitch list??
- Thread starter davegt
- Start date
RobbiZ4 said:Yeah, but that won't last for the next decade.
I also saw the following attempt with thick, fat brake lines, that worked for only 8 months. It was too stiff and teared the wires.
20200422_101821_small.jpg
For your own purpose you can risk everything. But replacing it for others, I never would risk anything in that critical and expensive area than OEM parts.
Hi Robbie,
Thanks for the feedback on that. Its really appreciated. I understand that in running a business, a local repair will not do the job and replacing the loom is the only way to go as a professional.
Having said that, a novice may be able to locally repair and replace the hose maybe using something akin to the connectors shown below with a short length of hose between?
As to what the correct diameter is, I don't know I just guessed at 4mm so this would need to be worked out. As to what type of hose that would be flexible enough to not wear out the cables (like those brake lines above), I don't know. As to whether it can deal with the pressure, I don't know (though it did say 312bar for the connector). This may be a cheaper fix than replacing the line for a novice, and if it gives the item 4-5 more years then I imagine that is long enough before the full loom would need replacing regardless.
I think this is worth a little bit more digging if it can potentially stave off the requirement for a £1000 loom plus 12hrs labour.
Tameson 4mm couple: https://tameson.com/fittings/hose-pipe-connector/compression-fitting/2-connections/straight-union/brass/fl2s-o-b-04-4mm-brass-straight-compression-fitting-150-bar-din-en-1254-2.html
Gates couples: https://www.gates.com/gb/en/construction/fluid-power/industrial-hose.html
Edit: I'm in no way trying to steal work away. I just think there may be a cheaper fix than a £1000 loom to fix one broken hydraulic line. These are repaired and replaced all the time in excavators and construction machinery, so figured there may be some solutions out there that didn't require removing and replacing the entire set.
RobbiZ4 said:
I think you may have taken my comment slightly out of context. There are numerous companies that will fix construction machinery and provide localised repairs to hoses; albeit, not with hoses found anywhere on the web (I was being pro-active and providing an example to help get my question across). I was asking a question as to whether there are connectors that can be used to aid a cheap'n'dirty fix and if there are any drawbacks to this, which you have kindly pointed out with the differing hydraulic ram pressures inducing different speeds to either side of the roof and tripping the control module; thank you.
If I was to attempt such a repair though, it would be pertinent to try and keep a replacement hose as close to the original length as possible, the same diameter, and same material grade if possible to ensure the same Poisson's ratio and maintain a similar hydrostatic head to the OEM cable on the other side. Please correct me if I'm wrong as I am just a structural engineer, so this is a bit outside my area of expertise.
But if I was to think out loud, you showed a brake hose that someone had tried and as you mentioned it was functional for 8 months (albeit, destroying the wiring in the process) I would have thought that there is a bit of tolerance in the sensor and in the ram. I'm guessing again here, but I would have thought there is a difference in diameter and stiffness of the brake hose in comparison to the OEM hose, which would give a different pressure and thus a different speed. But as it seemed to work for 8 months as you said, maybe the difference in pressure isn't enough to upset the CTM, and the only issue is rubbing of the wiring.
I understand that replace is always better than repair and your experience with these roofs is significant, but I'm still confident that there is a way to make a patch repair without replacing the entire loom, and maybe get another 4-5 years out of it and save a few thousand to boot.
Well there use to be loads of hydraulic pipe companies around this way, i'm sure a quick visit to one of those places would yield a suitable connector. Any change in diameter wouldn't significantly effect the operation of the roof, pressure is always constant, flow and speed might change though, but any connector will surely have a bore to match the pipe.
What is guaranteed here is BMW aren't making these themselves. They also have to make the spec of all parts available to the wider market after a few years. I can't see why any good quality hydraulic hose manufacture couldn't make these to the exact factory spec, or even exceed it if the original spec isnt proving very robust (like meyle HD parts for example) if they wanted to.
