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Discussion Starter #1
Am I going to have to bleed the ABS unit after I replace these hoses? I'm guessing no since they are downstream of the ABS, but I just wanted to make sure. I plan on having the brake pedal slightly depressed while I replace all the hoses to help minimize fluid loss.
 

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Can you get away without having to bleed the brake system and to activate the ABS solenoids during the process, is that your question?

Answer: By pressing the pedal will stop the master from draining all the fluid while you cut your fingers up, and bend your arms like a pretzel fighting those two short lines. You will however introduce a ton of air into the brake system, forcing you to re-bleed and more than likely you will have to activate the purge cycle in the ABS to get all the air out, which will also flush out all the old fluid at the same time so there is a benefit!
 

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Discussion Starter #3
I'm not saying I'm not going to bleed the system at all. I'm only asking if replacing those two lines will require bleeding the ABS module with INPA in addition to the usual brake bleed procedures. I will already be replacing the lines at the calipers and will bleed the brakes and clutch slave with a pressure bleeder, which has worked well for me in the past on other cars. Just wanted to hear from people that have replaced the short hoses in the engine bay and whether or not they had to bleed the ABS, seeing as those lines are very close to the module.
 

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Yes, you have to bleed the ABS unit electronically if you replace those.
 

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Yes. I replaced these lines along with the four corners and tried bleeding manually, but it still needed the ABS to electronically bled as well. Im assuming because there is air in the lines being replaced.
 

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Actually I will disagree with prior posters, you don't need to bleed ABS unit when replacing these hoses because they are downstream from the ABS unit. Actually with the hoses disconnected, the brake fluid flow rate is very slow, so if you do 1 at a time and it takes you 1-2 minutes from disconnecting each hose until putting a new one in, you will lose very little brake fluid. If you brake reservoir is full at the beginning, you don't run the risk of getting air into the ABS unit. Obviously if you disconnect the lines and leave it overnight, then it is a different story. Also it is convenient to combine this job along with valve cover gasket replacement because when you remove the passenger side valve cover you will have a lot more room. It is not necessary to remove the valve cover to do this, but just saying that it helps.
Once you replace both of these hoses you have to bleed both rear brakes because that is where these hoses go to. You don't need to bleed the fronts.
 

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Discussion Starter #7
Actually I will disagree with prior posters, you don't need to bleed ABS unit when replacing these hoses because they are downstream from the ABS unit. Actually with the hoses disconnected, the brake fluid flow rate is very slow, so if you do 1 at a time and it takes you 1-2 minutes from disconnecting each hose until putting a new one in, you will lose very little brake fluid. If you brake reservoir is full at the beginning, you don't run the risk of getting air into the ABS unit. Obviously if you disconnect the lines and leave it overnight, then it is a different story. Also it is convenient to combine this job along with valve cover gasket replacement because when you remove the passenger side valve cover you will have a lot more room. It is not necessary to remove the valve cover to do this, but just saying that it helps.
Once you replace both of these hoses you have to bleed both rear brakes because that is where these hoses go to. You don't need to bleed the fronts.
Thanks. That was my thinking as well but just wanted to hear from others who have done this. I plan on replacing them one at a time and immediately installing the new hoses. I will also try to cap the upper hard line while I am dis/re-connecting the other end of the hose to minimize fluid loss even further.

That being said, if I find that after normal bleeding I still have air in the lines and want to activate the ABS unit, are you all using INPA or DIS for this? I actually have both, but I read somewhere that INPA doesn't have this option on the E39 for some reason.
 
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