Rear brake pipes

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dooce
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Post Wed Dec 19, 2012 3:25 pm

The rear brake pipes on my touring has two sets of rubber flex hose, for a total of four hoses. I am trying to replace the hard lines for an MOT, and do not understand why there is two per side, instead of one at the caliper. Can anyone think of anything wrong with just coming off the t piece straight down the trailing arm into the flex pipe at the caliper? It would make this job a lot easier, as right now I am considering dropping the petrol tank to do it.

There is a picture here of how they are set up, those are the first flex hoses:
Image

That was found here, posted by Grrrmachine. http://www.e30zone.net/modules.php?name ... brake+pipe

http://realoem.com/bmw/showparts.do?mod ... g=34&fg=15
Grrrmachine
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Post Wed Dec 19, 2012 3:35 pm

You need the flexi pipes from the T-piece to the trailing arms because the trailing arms move up and down :D If you had solid lines from the T-piece all the way down the arms, you'd snap them in about two minutes as the suspension moved.
daimlerman
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Post Wed Dec 19, 2012 3:53 pm

This is perhaps the most frustrating maintainance job on an E30!

A 'crows foot' 14mm socket gadget will reach over the rear beam to hold the flexi whilst you thread an 11mm spanner up to the hard line.
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FinalD
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Post Wed Dec 19, 2012 3:56 pm

Took me a while to work out what you meant, but Grrrmachine has covered it. You need flex in areas where there will be movement, ie between the trailing arm and the chassis and the trailing arm and the caliper.

Edit: As for replacing the lines....I removed the rear beam to do mine....but then I also needed to get a grinder in to cut off one of the lines as it was rusted solid.
dooce
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Post Wed Dec 19, 2012 4:51 pm

Yeah, I realized that when I went back to look at it again. I was able to get all the pipes off without too much hassle though.
pacerpete
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Post Wed Dec 19, 2012 5:07 pm

The move when doing this very sad job is to cut the rubber hoses and use a deep 14mm socket on the remaining stump with a proper 11 mm brake pipe spanner on the 11mm. Using ordinary spanners will end badly .
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Brianmoooore
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Post Wed Dec 19, 2012 7:13 pm

As pacerpete hints at, the way to do this is to cut, destroy and renew everything - all hard lines, flexis, and the U shaped spring clips that hold the hoses to their brackets. If you twist the (rusty) spring clips with a pair of side cutters or needle nosed pliers, they will easily break in half, allowing the piece of cut hard line and flexi to be removed without undoing anything. Cut all theee pipes near the tee piece, and twist the whole thing anticlockwise while trying to undo the fixing bolt.
capnmchl
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Post Wed Dec 19, 2012 8:16 pm

If you're replacing solid lines, just cut them as close to the union as you can and bang a 6 point socket on there. If you have to use a spanner, make sure it's a crows foot. Lots of penetrating fluid.