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Just noticed that they're not stock and one of them in failing, so I'm going to replace them. If they go into the DSC unit it means I'll have to do a GT1 bleed to clear the air out of it. But, if they're going out from the unit, I can just pressure bleed it like normal...

Thanks!
 

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I believe that these hoses are from the DSC to the rear brakes. (items 3 & 4)



<TABLE cellSpacing=0 border=0> <TBODY> <TR> <TD class=r00>03</TD> <TD class=r01>Brake hose, left</TD> <TD class="r00 p1">M12</TD> <TD class=r01>1</TD> <TD class=r00>09/1998</TD> <TD class=r01></TD> <TD class=r00 noWrap>34321162616</TD> <TD class=r01 noWrap align=right>$38.98</TD> <TD class=r00></TD> <TD> <CENTER></CENTER></TD></TR> <TR> <TD class=r10>04</TD> <TD class=r11>Brake hose, right</TD> <TD class="r10 p1">M10</TD> <TD class=r11>1</TD> <TD class=r10>09/1998</TD> <TD class=r11></TD> <TD class=r10 noWrap>34321162612</TD> <TD class=r11 noWrap align=right>$38.98</TD> <TD class=r10></TD></TR></TBODY></TABLE>
RealOEM.com   BMW E39 M5 Rear brake pipe ASC/DSC
 

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AGM5 has it right.

All sorts of fascinating discoveries about E39 M5 brake lines.

Like the fact that they use different diameter lines and nuts for different sides.

Like the fact that the MC lines feed brakes, clutch AND the DSC pump.

Like the fact that a majority of the lines run INSIDE the engine compartment because that is where (stupidly) the ABS unit is located (the one that always gets in your way when you are trying to work on the passenger side of the engine).

And so on. I am so bored and should be at Timmayfest. ARGH.

--Peter
 

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AGM5 has it right.

All sorts of fascinating discoveries about E39 M5 brake lines.

Like the fact that they use different diameter lines and nuts for different sides.

Like the fact that the MC lines feed brakes, clutch AND the DSC pump.

Like the fact that a majority of the lines run INSIDE the engine compartment because that is where (stupidly) the ABS unit is located (the one that always gets in your way when you are trying to work on the passenger side of the engine).

And so on. I am so bored and should be at Timmayfest. ARGH.

--Peter
Yes. Yes you should have been there; as you were sorely missed. :sad3:
 

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Does anyone have a picture of how to get a wrench on these lines? What tools are you guys using to replace them? I tried my flare nut wrenches and couldn't really get at it so decided to leave it for now, but I would like to change them myself if I can.
 

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I replaced both of theses hoses in my car about a year ago when one of them burst. When I replaced them, I covered both of them with a piece of high temp aircraft grade tubing (good to about 2000 degrees) to give them added protection from the heat since they are located so close to the passenger side exhaust manifold. I also replaced them with steel braided hoses rather than the OEM rubber ones.
 

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Resurrection
I just had one of these hoses burst on my M. Picking the new hoses up tomorrow. Looks tight but do-able. Any tricks to getting in there other than maybe removing the air box? I assume normal brake bleeding afterward?
 

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I just had one of these hoses burst on my M. Picking the new hoses up tomorrow. Looks tight but do-able. Any tricks to getting in there other than maybe removing the air box? I assume normal brake bleeding afterward?
It is tight, but many have done it. I haven't with an engine in the way, so I don't have tips for that. Yes, normal bleeding is fine.
 

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Finished up both flex lines today. The lines cost about $86 for the new lines from the daler. Luckily a semi-local dealer had the lines in stock. So, a few notes while fresh in my head:

Inventory:
17mm flare or ratcheting wrench (for flex line)
14mm flare or ratcheting wrench (for flex line)
11mm flare wrench (for hard lines)
2 bottles dot 4 brake fluid
Can of brake cleaner
34 32 1 162 616 brake line (14mm)
34 32 1 162 612 brake line (17mm)

I took off the fresh air filter assembly to get some more room to wrench because there is very little room to move. I found the lines were threaded together ver tightly. So, I cut the rubber portion of the line. I then put the flare wrench on the hard line (11mm) and used a ratcheting wrench (14mm and 17mm) on the rubber line section. This way I was able to get more torque to break the threads loose (no point in apply torque to the 11mm hard line and risking rounding off the edges). I suppose you could also use a 12pt wrench or even a deep socket since the line is cut. I would also suggest loosening up and/or removing the bottom tray of the car. I dropped my wrench at lease 3 times and had to fish it out from underneath the car. Polished tools in combination with brake fluid= very slippery. And since the line burst, there was brake fluid everywhere underneath the car. I cleaned that all up with the brake cleaner then some simple green and water. Bled all 4 brakes, pumped the brakes a few times to get pressure back and voila! Job done.

(the hard lines with blue tape in the picture below are the two lines to the rear that were replaced)
 

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Whoever replaced those previously (or maybe you) must have bent the metal lines a little. That one hose should be pretty much straight on like the other one. Shouldn't hurt anything as long as it's not touching anything or too close to the exhaust.



Finished up both flex lines today. The lines cost about $86 for the new lines from the daler. Luckily a semi-local dealer had the lines in stock. So, a few notes while fresh in my head:

Inventory:
17mm flare or ratcheting wrench (for flex line)
14mm flare or ratcheting wrench (for flex line)
11mm flare wrench (for hard lines)
2 bottles dot 4 brake fluid
Can of brake cleaner
34 32 1 162 616 brake line (14mm)
34 32 1 162 612 brake line (17mm)

I took off the fresh air filter assembly to get some more room to wrench because there is very little room to move. I found the lines were threaded together ver tightly. So, I cut the rubber portion of the line. I then put the flare wrench on the hard line (11mm) and used a ratcheting wrench (14mm and 17mm) on the rubber line section. This way I was able to get more torque to break the threads loose (no point in apply torque to the 11mm hard line and risking rounding off the edges). I suppose you could also use a 12pt wrench or even a deep socket since the line is cut. I would also suggest loosening up and/or removing the bottom tray of the car. I dropped my wrench at lease 3 times and had to fish it out from underneath the car. Polished tools in combination with brake fluid= very slippery. And since the line burst, there was brake fluid everywhere underneath the car. I cleaned that all up with the brake cleaner then some simple green and water. Bled all 4 brakes, pumped the brakes a few times to get pressure back and voila! Job done.

(the hard lines with blue tape in the picture below are the two lines to the rear that were replaced)
 

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Actually, that's a picture of the new lines I just installed. The line that burst was the curved line and it was original to the car, so we can blame the factory workers for that. Now that you mention it, it did burst around the crimp...probably because of the bend. I'll play with the hard line a bit...maybe can get it a little straighter. Then again, the old lines were 15 years old with 195K ... so not entirely an eminent issue.
 
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