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1Back to top Go down   ABS brake hoses Empty ABS brake hoses Mon Jun 14, 2021 10:29 pm

magicflem

magicflem
active member
active member
Hi,
I am new to BMWs and would like some advice on how to change front brake hoses and inparticular the hose from master cylinder to ABS line.
Regards,
Kim

    

2Back to top Go down   ABS brake hoses Empty Re: ABS brake hoses Mon Jun 14, 2021 11:24 pm

Two Wheels Better

Two Wheels Better
Moderator
Moderator
@magicflem wrote:Hi,
I am new to BMWs and would like some advice on how to change front brake hoses and inparticular the hose from master cylinder to ABS line.
Regards,
Kim
Where to begin? Have you got a basic comprehension of brake hydraulics, a brake hose spanner, & a Mighty Vac or equivalent? It's universal if you understand the lingo. In bleeding the individual circuits, front & rear, after replacing the old rubber hoses (I recommend braided versions) you will be pulling the fluid (DOT4) through the ABS pump so it's fairly straightforward.


__________________________________________________

1970 R60/5, OZ '77 R75/7-R100, '85 K100'87 K75C, OZ '87 K100RS, '93 K11-K12 Big Block, '93 K1100RS, '95 R100-Mystic, '96 K1100RS, '98 K1200RS, '00 K1200RS, '02 K1200RS, '03 K1200GT, '04 R1150R'04 R1150RT, '05 K1200S, '06 K1200R, '07 K1200R, '09 K1300GT & 2013 R1200RT-Polizei  - Beemers owned still or sold.

~We all believe what we want to believe in - Rob Dickinson
    

3Back to top Go down   ABS brake hoses Empty ABS brake hoses Mon Jun 14, 2021 11:35 pm

magicflem

magicflem
active member
active member
I am familiar with brakes, bleeding etc but would like some detailed advice on how to change front brake hoses and in particular the hose from master cylinder to ABS feed line.

    

4Back to top Go down   ABS brake hoses Empty ABS brake hoses Wed Jun 16, 2021 11:00 pm

magicflem

magicflem
active member
active member
Hi,
Can anyone please help with advice?
Regards,
Kim

    

5Back to top Go down   ABS brake hoses Empty Re: ABS brake hoses Thu Jun 17, 2021 4:11 am

TacKler

TacKler
Life time member
Life time member
Here goes.  

I see you have a K100LT whereas mine is a 75S.  I assume the your ABS system is the same as mine and is a combination of metal tubing to the ABS modulators and flexible brake lines.  There is also a fixed tube between the RH and LH brake calipers with the brake line running to the RH and the bleed nipple on the LH only.  I also assume you will be doing this whilst sitting on the garage floor and not on an elevated platform.  

If you have not done this before, then I would suggest: 

  • give yourself at least half a day to do the job 
  • remove yourself from small animals, children and significant other 
  • advise all others to ignore shouty, angry, swear words except for the world Help 
  • be self sufficient in brew gear, grog and snacks 
  • smile  Smile 


Underneath tank connector 

Firstly you have a massive big fairing which is going to interfere with access on the RHS.  At the very least remove the lower RH portion of the fairing.  You will need access to where the modulator tubing runs slightly right of centre under the spine and it joins the flexible brake line.  Also remove the access panel with the grill directly in front of the radiator.  Two small panels at the rear of this fairing to enable this and there should be a cutting for the brake line access.  Fun so far isn't it?   Maybe a couple rubber boots in there.  

When you have these removed then jam an old towel or a bunch of rags on top of the radiator and directly below the brake line joint because whichever way you look at it you will get dribbling brake fluid (DOT 4) and it will take the paint of anything it comes into contact with.  If in doubt flush with water.  Whilst you are there remove the rear piece of the front mudguard (as it is in two pieces and they both come off together).  You need to take this off when it comes to the front brake calipers because there is a joint below it.  

When you have the mudguard removed place rags on the tyre to protect it from dribbling brake fluid or jam a piece of cradboard in there to deflect any drips.  

Whilst you are getting frustrated, it is a good idea to have a small crate or a seat to sit on or you may sit directly on the floor.  The tools you need here are a 14mm spanner and one slightly smaller.  It is a bugger to get into as the join is below part of the frame and surrounded by wiring.  If you have fat hands then you really are phucked.  Looking at my 75S I could not get a spanner in there apart from the front 14mm.  

You will need one spanner on the modulator brake line and a 14mm on the front connection for the brake line.  You need two spanners to do this as one is required on each connection.  I used to maintain aircraft once so I don't consider it a difficult job.  However I expect you will.  Memory tells me they undo anti-clockwise and I expect your spanners will slip off a few times  ABS brake hoses 61740   When undone then jam more rags in there so the drips of oil from the modulator tubing don't come into contact with paint or plastic, etc.  

The brake line connected to the lower surface of the master cylinder on the right handle bar is also a 14mm.  DO NOT disconnect this one until you have undone the the previous one first.  Others will say why not but too me it makes life easier for various reasons.  Once you have this piece off then there will be drips from the master cylinder so stick a rag in there straight away.  Even better have the rags underneath before you start.  Pull the brake line out slowly remembering how it is routed in there and to avoid oil drips.  Then fit the new braided brake line straight away to the modulator join but do not tighten.  Attach the master cylinder end finger tight and tighten the modulator end first.  Then the master cylinder end.  There is no need to drain the front brake master cylinder or to take the cap of until you start bleeding.  

Front calipers 

Under the rear section of mudguard you have removed there will be a brake tube connecting to the flexible brake line.  

Place rags around the the RH brake caliper. Tie one around the brake tube just below the join.  You are going to crack this one after the next procedure.  You do not want any brake fluid dripping onto brake discs or brake pads.  You can place a piece of cardboard on the ground to absorb any stray drips if you wish.  Best to jam it under the tyre so it does not move.  

There will be a second brake modulator tubing line running in parallel to the one to the master cylinder and there is a connector around where you have taken the grill faring off.  Undo it with both spanners as before and ensure you have the new replacement line handy and ready to go.  Try to keep the end you have disconnected upright by taping it up or it may still be zip tied to the ABS wire.  This is to prevent the brake fluid in the crossover tube between both front brake calipers bleeding out.  When it comes to bleeding the front brakes this will make your life so much easier if you do not have a pressure bleeder which I assume you do not.  

When you are ready, crack the brake line that you are going to replace on the RH caliper.  Then slowly undo it pushing down on the bit turning in an attempt to minimise the fluid loss from the crossover line.  When it is loose and completely off immediately place your finger over the opening and hold it there.  Let the other line drip into a container to collect the fluid and prevent a mess.  When you have done that use the same hand to wind on the new line to where you finger was holding the fluid at bay.  Tighten finger tight whilst holding the open end up to prevent fluid loss.  Tape it in place.  Handy hint - have the tape already torn off and ready to use.  Tighten join with both spanners, then take a deep breath and relax.  

If you have a medical grade syringe you can fill this with brake fluid and use this to top up the brake line you are about to connect.  Handy hint - ensure you lubricate the rubber side surface with brake fluid so the syringe moves easily and does not stick making a mess.  Only a small amount of fluid will be needed.  All this does is reduce the amount of air in the brake lines when it comes to bleeding them.  Again I assume you will be bleeding by hand.  

From here reconnect the brake line to the modulator tube and tighten with two spanners.  If you have left the ABS wiring line attached to the old brake line, then zip tie it to the new one.  

Stand back and have a think about what you have done.  Check all joins for tightness and ensure all rags removed.  

Job done.  When it comes to bleeding, it will take a while as there is more fluid in the system compared to a non ABS system.  I'll let someone else explain the joys of that.  

Points to remember: 

  • brake fluid destroys paint 
  • use lots and lots of rags 
  • go slow, don't rush 
  • avoid making a mess 
  • take photos as you go, if you can  
  • use white spirits to clean everything, clean as you go 
  • if you use a syringe, clean in white spirits when finished, then place in a clip seal bag and mark for future use 


And most importantly, prepare everything before you start.  

Others will no doubt disagree with some of what I have said but I don't care.  I know what works for me and like most have learnt the hard way.


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Red 1991 K75S
    

6Back to top Go down   ABS brake hoses Empty ABS brake hoses Fri Jun 18, 2021 1:38 am

magicflem

magicflem
active member
active member
Hi and thanks for the detailed info.
Would you have a picture of spanner access to  "where the modulator tubing runs slightly right of centre under the spine and it joins the flexible brake line"?
Regards,
Kim

    

7Back to top Go down   ABS brake hoses Empty Re: ABS brake hoses Fri Jun 18, 2021 11:25 pm

TacKler

TacKler
Life time member
Life time member
It is quite difficult to take an image of that join which is directly underneath the electronic ignition module which is aft of the steering head stem.  To the right of it are a bunch of wiring looms and the brake line from the front master cylinder which enable a small opening to see the join.  

As I do not have a digital SLR allowing me to manually focus on the exact item, this is the best image I can obtain with my current camera:    

ABS brake hoses Dscn8111

The piece of black heat shrink with what appears to half of the letter "O" on it is the 14mm connection side with the connection directly to the left of it.  To the left of that is the rubber ring used to prevent vibration and wear on the modulator pipe.  Directly above is the electronic ignition module.  

To the right of the wiring looms are the front brake join between the modulator tubing and the flexible brake line with ABS wiring beside it.

So hopefully this will point you in the right direction.  

Wow, just noticed this is my 1,000th post  ABS brake hoses 723598


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Red 1991 K75S
    

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