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Brake hose replacement


neilsr1100rt

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Hello all.  While recently replacing the rear brake pads on my 2000 1000RT, I noticed a pinhole leak on my rear brake hose and am looking to replace it with a steel braided hose as an upgrade.  My thought is that when simply swapping out one brake hose for the new one, I was hoping to just bleed the system at the rear caliper nipple fitting and be done with it.  One video I watched had a guy replacing all his hoses and bleeding the entire system from the ABS unit with the tank completely removed and basically the bike stripped of all faring's, etc.  My aim is to avoid that hassle and simply pump the rear brake and bleed the rear caliper as previously mentioned.  Any feedback as to whether this approach is correct?  Do I really need to bleed the whole system and involve the ABS unit, which isn't functioning anyway?  Thanks for the advice.

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If all the hoses are the still the original OEM rubber ones I would suggest to replace them all as they are way past their safe service life and you will be doing the other ones in the not too distant future.  To answer you question, if you don't have the brake fluid in the reservoir run dry you should be fine but also have enough fluid to put enough clean fluid through the entire circuit until it flows clear at the caliper nipple.   When I replaced my  brake lines on my '99RT I used a combination of a mighty vac to pull fluid through and brake pumping with release at the brake nipple and had no issues with spongy brake feel.

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37 minutes ago, neilsr1100rt said:

Hello all.  While recently replacing the rear brake pads on my 2000 1000RT, I noticed a pinhole leak on my rear brake hose and am looking to replace it with a steel braided hose as an upgrade.  My thought is that when simply swapping out one brake hose for the new one, I was hoping to just bleed the system at the rear caliper nipple fitting and be done with it.  One video I watched had a guy replacing all his hoses and bleeding the entire system from the ABS unit with the tank completely removed and basically the bike stripped of all faring's, etc.  My aim is to avoid that hassle and simply pump the rear brake and bleed the rear caliper as previously mentioned.  Any feedback as to whether this approach is correct?  Do I really need to bleed the whole system and involve the ABS unit, which isn't functioning anyway?  Thanks for the advice.

Afternoon  neilsr1100rt

 

The fluid in the rear system will siphon out as you change the rear hose.

 

If you first top the rear brake reservoir off, then open the rear caliper bleeder slightly, then slowly push the rear brake pedal down (then retain it in the held down position) that will close off the the brake cylinder vent hole & prevent fluid siphoning out when you remove the old hose & install the new one.   

 

After replacing the rear hose then bleed as normal. 

 

If you prevent the rear brake system from draining between the master cylinder & ABS unit  that will prevent air from getting into the ABS  pump upper chamber so you won't have to bleed at the ABS bleeders.

 

 

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When replacing the rear brake hose, the most likely thing is that you will get air into the circuit. You might be fortunate and keep fluid in the right places, but without a lot of experience, it is unlikely. But, don’t despair.

 

 The ABS unit is the high point in the rear circuit. If you get air in there, no amount of pumping the rear brake pedal will move the fluid up to the abs and then to the caliper. You don’t have to remove the tank and bleed at the abs. If you have access to a vacuum bleeder, that will have the ability to pull the fluid up from the reservoir and through the circuit. If you don’t, then a bleeder bag or a syringe, connected to the caliper bleed screw will let you push the fluid up from the caliper to the abs and then to the reservoir.. If you use the bleeder bag or syringe, remove most of the brake fluid from the reservoir first. Once the fluid starts filling the reservoir, the entire circuit is full of brake fluid. You can then bleed the rear circuit normally.  This is really very easy to do.

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Hello Paul De, dirtrider and Michaelr11.  Thanks for your insights regarding my question.  All feedback has been extremely beneficial and I plan on taking the advice to replace all the brake hoses, front and rear, as well as purchase a vacuum bleeder to help pull off the job.  They're more inexpensive than I thought, and it won't be the last time I'll be needing the tool.  Thanks again for your prompt responses and sound words.  Happy ridin'.

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  • 3 weeks later...

Neil- I replaced all of my lines a couple of years ago on my 96 RT. Used a set of Galfer lines. took a while but wasn't really all that difficult. Im due for a fluid change. I also did a front master cylinder rebuild, thought I should as long as i had the system opened up. Funny, but I never found a rebuild kit for the rear MC. Dark dark dark fluid came from the ABS unit when I bled it out. Yikes!  I thought the mity vac would be the magic bullet, but I still used the pump, hold, bleed technique along with the mity. Really keep an eye on the fluid in the res, I went dry at least once on both front and rear, had to start over. Those SS lines look sooooo good too. Dave

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I actually do both mighty-vac and pump and have had very good results.  I have to take my wife out to a nice lunch (Pre-Covid) for her to do the lever pumping, because see doe not count this as together time.  This spring fluid change out will require something I whip up in the kitchen as compensation.

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  • 6 months later...
MT Wallet

I'm changing my brake lines and bleeding the system on a 2000 R1100RT. So my initial question is how much torque to apply to the bleeder screws/nipples? I have a tendency to over tighten things without adult supervision.

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dirtrider
7 minutes ago, MT Wallet said:

I'm changing my brake lines and bleeding the system on a 2000 R1100RT. So my initial question is how much torque to apply to the bleeder screws/nipples? I have a tendency to over tighten things without adult supervision.

Evening  MT Wallet

 

My BMW service manual shows 7nm front bleed screws & 4nm rear calipers bleed screws. 

 

I haven't ever actually torqued those bleed screws so can't tell you how close those service manual torque values are to what feels right.   

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Lowndes

MT,

 

Be sure to shim the brake pads against the disc to push the pistons into the calipers as far as possible.  Wood door frame shims work well.  The pistons and cylinders in the calipers are on dead-ends (do not get bled) in the hydraulic circuit so pushing as much of the fluid out as possible while replacing the DOT4 will help. 

 

GOOD IDEA replacing all the OEM flexible lines. 

 

 

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Lowndes thanks for that suggestion. I've bleed the back and it seemed that I was moving more fluid into the hose than I should have been.

I installed Galfers and found one item in the bag with the new banjos and crush washers I can't account for. It looks like a little brass disc about 1 cm in dia. with a small hole on one side and a larger hole on the other. Before I replace the tupperware can anyone tell me what it is/does and where it goes? No instructions came with the hose kit.

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2 hours ago, MT Wallet said:

Lowndes thanks for that suggestion. I've bleed the back and it seemed that I was moving more fluid into the hose than I should have been.

I installed Galfers and found one item in the bag with the new banjos and crush washers I can't account for. It looks like a little brass disc about 1 cm in dia. with a small hole on one side and a larger hole on the other. Before I replace the tupperware can anyone tell me what it is/does and where it goes? No instructions came with the hose kit.

MT Wallet

 

Until Lowndes gets here don't button anything up yet.

 

I believe that washer is called an Inversor, go to this web site  (   Galfer Instructions for BMW (galferusa.com)  then look up the instructions for your brake line kit. Probably look for rear brake instructions. 

 

I believe that Inversor might be directional so you might have to call or use the Galfer tec line to find the proper install direction (if it is directional)  as usually Galfer directions are pretty vague. 

 

Added: those Inversor's are usually only needed  if you are trying to connect a flared line to a tapered DIN/ISO bubble flare seat. 

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Thanks DR. I had a conversation with a Galfer tech and he said it was for bridging two fittings connecting which were concave. I took my front lines apart and didn't find a concave connection. I looked at the original lines, including the rear and they were all concave but seemed to have convex lines connecting into them. Maybe there was an engineering change and the concave connectors meeting was pre 2000?? (hope, hope, hope,)

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41 minutes ago, MT Wallet said:

Thanks DR. I had a conversation with a Galfer tech and he said it was for bridging two fittings connecting which were concave. I took my front lines apart and didn't find a concave connection. I looked at the original lines, including the rear and they were all concave but seemed to have convex lines connecting into them. Maybe there was an engineering change and the concave connectors meeting was pre 2000?? (hope, hope, hope,)

Evening MT Wallet

 

If you needed that Inversor it would have been on the rear brake, as long as your steel line end fitting matches your brake hose internal seat then you are good to go. 

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DR, I don't have any drips or seepage at the rear fitting. Peddle felt spongy last night but today it feels firm. I bled through the ABS unit last night and the caliper. I'm nervous about things like this. I plan a little work trip to Michigan and I have zip for tools if I didn't do something right and need a fix.. I trailering the bike if all is well so its not like I'll be stranded if something fails. Thanks for all the help.

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We're both glad Dirtrider was here because I sure don't know about any inversor.  Didn't come with any of my Spieigler kits.

 

Be very careful torqing the banjo bolts.  They are hollow AND have side holes near the head that reduce the crossectional mass by about 60% and the tensile strength accordingly.  The good part is if you break a banjo bolt, the easyout hole is already there if you need it.

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9 hours ago, Skywagon said:

Lowndes....blasphemy....You said DR and Easy Out in the same paragraph.... We may have to get him a stiff drink.  :3:

Uh,        same post, separate paragraphs.

 

We'll get him some antidote anyway!!

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12 hours ago, Lowndes said:

 

Be very careful torqing the banjo bolts.  They are hollow AND have side holes near the head that reduce the crossectional mass by about 60% and the tensile strength accordingly

Haha, some folks have it in their head that a large diameter bolt requires large torque. Just enough torque to get a good seal to the mating surface in the case of a banjo bolt is all that is needed.  Can't even count the times that I have found bolts on some piece of equipment that the owner made too sure that a bolt wasn't going to come loose.   Drain plugs are notorious for being over torqued

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Paul De, Lowndes, Interestingly it only takes 15NM  or 130 in. pounds to torque banjos. I was kinda shocker that they came loose with so little effort. I'm usually one of those overtighten guys. I used to over tighten drain plugs on cars until I read somewhere it only take 14 Ft.Lbs. to do the job. It bothers me now to see some tech hanging on the wrench at the quick change oil shop.

Everyone thanks for the comments and help. You know when I disassembled the rear hose I've come to realize there was no inversor that hit the floor. So either it's not there, still there and I'm unaware that I'm reusing it or it never existed in my bike. Like DR suggested it's all good.

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