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kalali

Brake Caliper Weeping

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kalali

Hi. I noticed the right caliper on my 1999 R1100R is weeping lightly right where the two halves of the caliper meet. It only happens when I pull the lever. Is it possible that I overfilled the master cylinder when I bled the brakes or there are seals between the halves that need to be replaced? The bolts are tight but I did not open and retorque. Should I do that? The left caliper is bone dry. Bike has under 19K miles.

Thanks.

 

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AndyS

It should not be doing that.

Moreover, if the fluid can come out, there is air can get in.

Worse than that, brake fluid is hygroscopic, so it will be trying to absorb water.

The caliper is defective and should be stripped / repaired /replaced.

Are you still on the original brake hoses? If so, these are due replacement too. I recommend braided Stainless Steel hoses.

Trying to split those calipers at this age may throw up some challenges due to corrosion.

 

 

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kalali

Thanks Andy. I agree, it should not be weeping fluid but I guess what I'm asking is if there's the option of splitting the caliper and repair it as opposed to replacing the caliper. I don't see any signs of corrosion, at least nothing visually outside the shell so I wouldn't mind taking it apart and getting it fixed, if there's something like a seal that could be replaced. As for the lines, yes they are original and the replacement with SS line(s) is on top of my to-do list.

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Tri750

If you were in a rust free area, i wouldn't be concerned. "rubber chicken racing" sells the orings for the caliper halves. BMW does not.

 

Bit be very careful taking apart. Clean well and clean the pistons 360 degrees before you push them back in.

 

Yes, get the SS lines sooner than later and don't pump either master full stroke when you bleed them. A power bleeder or Mity Vac will do better.

 

 

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Lowndes

Hey, kalali,

 

Should NOT be leaking at all. If coming from between the halves it must be the O-ring or its seat. Only place it could be unless a line is leaking and running down onto the caliper.

 

These are some pics of when I had to split my calipers ('99 R1100S) two years ago. More Pics here. Decomposing OEM brake lines plugged the galleries and locked up my front wheel. EZPZ to split, but only clean one half of a caliper at a time and don't remove the piston seals if you don't have to. There are two different size pistons in each side and two different rubber seals on each piston. Wipe out each cyl and blow out the galleries with hp air. Extremely simple to reassemble - only one square section O-ring between the halves - but I could not find any torque values for the four bolts, Maybe Rubber Chicken would know.

 

+1 on the SS/Teflon brake lines, Spiegler or Galfer. Do front and rear rubber lines, everything but the steel lines. Also do the clutch line if yours is hydraulic. Your OEM's are way past due.

 

If Rubber Chicken doesn't have what you need, maybe Munich or Bevel Haven can help.

 

The conical hole nearest my thumb holds the O-ring. The mating side is flat except for the gallery (hole).

 

QCxK7QBq1OlYdN3zO88eeFmHuwOXiDDKAg-6lhyHr-TtGJbwsmpI2azT5APmUpHh4X9QJ1Pg4IdY8GuhNx055b8vEGHLCFmCx2Bo8LONk0-7b7G9d6Vy_ycYQxuQTEeel2kbTN3sYBcBGd5kC0xnDayJA3GLRVC8_vjbB-FbfagT3jocJVzh1MtLTpntSYjMG1yruFsQATM3OPPDUYprqzyZBiEP-ZIvWoTKIEIIvwSQKmG-A0fTJG5lh3ZCydY5Q-CPvkMkvUl4CkEYtATaqawzQ2-vr9LDzXdW7DxMDDNZuyERtG-6S2_W1H8o-vid-doapfwXAO3q3hfUNMYG84ayz2mAgT-xW4iXkvpvJEgre6p8ArkiaJNLe3Pws20nu6ybzECC289-OK6Al7Q_D_mIIunWK8rRMaSgwuarPeO1fdLesCxl4jhd7LGJsIwmVMDFjaAVivYThI81jX5EC-szknoQxIYao_gi_EZkHyNY1hesJAVPvasKCJpgDhCVaO0b-BaiOYNQWr82VMeJiv1lOoWJzgV31FzwlD_L51cVubuvfNQ_fwmO3gdIipTymYVhIJOVqfNoL5PtPYvmrZrEi4yUEVS3HbZEWh8RkRsE95TD1NW1kVO-DjRGnya8L4GnDcSyE8dIhZMw0sqviNQMTcADXM3h=w364-h647-no?.jpg

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kalali

Lowndes, thank you so much. This is very helpful. Appreciate it.

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BF204

For after you get the caliper sorted out, I just put Spiegler lines on my '99 R1100R last week. Seem to be very good quality, and after I got some help figuring out what the factory fill fitting was on my right front caliper (and ditching it), it was straightforward. Here's my thread... click for thread on factory fill fitting

 

And, under 19K miles!? Just broken in! Mine will hit 100K Km in the next few tanks (and I expect will go for lots more). Good luck!

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kalali

Hi. I expect the brake lines today and will try to install them this weekend. Quick question: did you keep your reservoir full while removing the OEM lines or you let it drip out empty - or removed the fluid before you started the process? That's the only part I am not sure about. The rest looks relatively straight froward. BTW, I'm leaving the caliper alone for the moment since the "weeping" is barely noticeable. Thanks.

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BF204

I used a big syringe to suck out the fluid out of the reservoir before removing the old lines. I put lots of shop towels over everything to try and keep drips from hitting paint. Wasn't as messy as I expected it to be. FYI, my '99R does not have ABS, so if yours does, the bleeding process etc will be different than it was for me. Good luck!

 

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Dave P

Kalali-probably not a bad idea to get rid of the old fluid. While I had the chance, I took apart the front MC and did a rebuild of the seals. If you have ABS, you will need the bodywork off anyway to switch out the lines and bleed the abs block. I took my front fender off as well.

 

As per Dirt Rider's suggestion, I burped all of the tiny bubbles out of the MC first. I used a combo of good old fashioned lever (and pedal) pumping and MityVac hand held to get the air out everywhere else. I think I did pretty well, took a while since I let both the front and rear go dry one time each!!! Used 2 pints of fluid for the whole job. Dave

Edited by Dave P

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kalali

Gentlemen, thanks for all the input. I had bled the brakes (without doing the ABS pump) using the MityVac a week or so ago before I decided to replace the lines so the fluid is pretty fresh. On the R all the connection points are exposed so I'm really hoping to get the job done and do a simple (re)bleed without the need to get into the ABS module if at all possible, even if it means having to keep the reservoir partially full. This probably means lots of towels and making a mess and having to work quickly so I'll evaluate the situation as it goes. It might help if I start with doing the line from/to the reservoir first. If anyone thinks this is a real bad idea, please tell me. Just trying to avoid having to remove the tank, etc., etc. Luckily I just need to do the front since the previous owner already replaced the rear line with aftermarket SS line.

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The Fabricator

I am a retired motorcycle mechanic. I have clean MANY brake caliper over the years.

 

If you let the caliper 'weep' at the seam [or anywhere] it will take the paint off. Then corrosion will commence.

 

I always take the pistons out [using compressed air to shoot the piston onto a rag OR the entire system intact, pushing the piston out by pumping the brake lever [add fluid to the reservoir]]. I always take the seals out to clean the grooves and then clean deposits in the piston bores, checking the fit by pushing the piston home [with out seals]. I prefer to use the old seals. HORRORS! Because...the following.

 

A musky brake is caused by several factors. [Rigidity of components is one]. The operative factor in focus now is DISTANCE THE PISTON TRAVELS.

 

This means the DISTANCE from the rotor to the piston.

 

Consider that if the DISTANCE is so great that the brake lever has to be pumped several times before ANY contact is made, this is using up lever travel without producing any contact. Now reduce that DISTANCE so that 1/2 the lever travel is used before contact is made. Now reduce the DISTANCE so that 1/4 lever travel is used. Continue this 'reduction' scheme. It is apparent that the closer the piston is to the rotor, the less lever travel is needed to initiate contact. Less lever travel=less mush.

 

The reason new seals will produce a mushy brake lever feel is this DISTANCE.

 

People don't realize the seals pull the pistons back AWAY the rotor when the brake lever is released. Just go to your MC, squeeze the brake lever, release, watch the pads pull back. The pads pull back because the pistons pull back.

 

The seals are square cross section. The seals grip the piston. When the piston moves a little [brake applied] the seals, while still gripping the piston, deform as the piston moves. When the fluid pressure decreases [lever released] the seals [still gripping the piston] return to their original shape, pulling the piston back. If the piston moves more than a little [due to brake pad wear], then the piston will slide SOMEWHAT through the seals.

 

New seals are supple compared to old seals. Old seals are harder and deform less, there fore, old seals will pull the pistons back less than new seals. I have cleaned MANY calipers on Japanese dual brake front ends. When the bike comes in, the lever action is very firm because the corrosion in the caliper prevents the pistons from retracting very much. Sometimes only the amount of the run out in the rotor. When I clean everything AND use new seals, the lever travel is extreme by comparison, such that I wouldn't be happy with that mushy feel on my bike. Try explaining to the customer used to firm lever feel and good performance from the brakes that a repair just that cost him $300 plus is proper. [They feel like they have air bubbles in the system! Did you bleed them?]

 

What about the old seals leaking? Doesn't seem to happen. 30 years experience. Never had a customer come back---about that.

 

Replace fluid. Yes. Fluid absorbs moisture. Why did I clean MANY calipers [and masters]? Moisture. Corrosion. Moisture causes corrosion. Incidentally, I do replace the rubber components in the master. The master is a much different than a caliper. A master piston will travel miles [kilometers]in its' lifetime; a caliper piston 1/4 inch [8 mm]. Increased wear. A clutch master AND slave piston also travel a lot.

 

The way I change brake [and clutch] fluid.

 

Don't loose the 'prime'. Prime means the system is purged of air so that the pumping mechanism is not trying to pump air. If it is pumping air, it will not work because it is not able to pump air. The pump [master cylinder] will loose prime if air is allowed to enter the system at the pump location. Air down at the caliper end is ok. Remove the calipers, then bind the brake lever to the handle bars. [Rubber band?] If air can enter the master cylinder reservoir, the the fluid will drain out of the master, loosing the 'prime'. Binding the lever in the applied position will close off the bottom ports in the master, thereby preventing drainage. Do your caliper work. Connect the caliper. Release the brake lever. Suck out fluid from the master reservoir to the bottom. Fill with fresh fluid. Attach a clear tube to the bleeder valve on the caliper, looping the hose higher than the bleeder.. TRIGGER WARNING!!! STOP READING NOW TO PREVENT SHOCK!!! [Now comes the heresy!] Open the bleeder valve. Start pumping without letting the fluid level in the reservoir fall so low it sucks air into the 2 ports in the bottom of the reservoir. Just pump away. The pump [if it has not lost its' prime] will pump out more than it sucks back when the lever is released. THAT IS A SHOCK TO THOSE WHO HAVE ALWAYS 'PUMP-OPEN BLEEDER-CLOSE BLEEDER'-RELEASE LEVER'. Those people say it will not work. That it will suck air at the bleeder. They see air in the hose at the bleeder. That air is coming from around the bleeder threads and is not getting into the caliper.

 

I did it that way for 30 years.

 

I did it that way to my R1150GS with ABS when I replaced the brake lines. The fluid will pass through the ABS pump just fine. There may be a section of un-purged old fluid in the pump. I am not concerned. I have replaced fluid on an ABS system at the pump. What a hassle. Spilling that corrosive fluid onto all those components with all those cracks and crevasses that can not be cleaned without disassembly. Yuck.

 

 

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AndyS

I did it that way to my R1150GS with ABS when I replaced the brake lines. The fluid will pass through the ABS pump just fine. There may be a section of un-purged old fluid in the pump. I am not concerned. I have replaced fluid on an ABS system at the pump. What a hassle. Spilling that corrosive fluid onto all those components with all those cracks and crevasses that can not be cleaned without disassembly. Yuck.

 

I am not understanding.

On the 1150 the brake system is divided 4 ways:

a/. Front Master cylinder to Servo

b/. Servo to Front wheel

c/. Rear Master cylinder to Servo

d/. Servo to Rear wheel.

 

You say "the fluid will pass through the ABS pump just fine" but it doesn't pass through. They are independent systems.

 

 

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kalali

 

You say "the fluid will pass through the ABS pump just fine" but it doesn't pass through. They are independent systems.

 

 

My understanding (or assumption) is this statement is true for the ABS-II system thus frequent bleeding at the wheels will ultimately/gradually flush the pump. The Servo system is probably different.

Edited by kalali

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dirtrider

I did it that way to my R1150GS with ABS when I replaced the brake lines. The fluid will pass through the ABS pump just fine. There may be a section of un-purged old fluid in the pump. I am not concerned. I have replaced fluid on an ABS system at the pump. What a hassle. Spilling that corrosive fluid onto all those components with all those cracks and crevasses that can not be cleaned without disassembly. Yuck.

 

I am not understanding.

On the 1150 the brake system is divided 4 ways:

a/. Front Master cylinder to Servo

b/. Servo to Front wheel

c/. Rear Master cylinder to Servo

d/. Servo to Rear wheel.

 

You say "the fluid will pass through the ABS pump just fine" but it doesn't pass through. They are independent systems.

 

 

Morning Andy

 

The very early 1150GS (remember the 1150GS came out earlier than the 1150RT) did have the old ABS-2 system. But it didn't have a pump (servo pump) as it had an ABS modulator (chain & piston system).

 

 

 

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AndyS

Thanks DR.

Thanks for jogging my memory on that.

However for any casual readers here...remember that what is described in The Fabricators post will nit work on your 1150RT and later 1150GS' that have iABS.

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PatML

Fab detailed explanation thank you. I am about to service my front brake calipers (2001 R1150RT) and this gives me enough confidence to do it without forking out for the expensive seal and piston kits. Even starting to think I might split the calipers despite reading warnings that they will warp. Guessing that if I do the four bolts a little bit at a time each, like cylinder heads, to keep the pressure even across the whole thing, it should be OK. Any views on reusing the o-rings here?

 

 

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kalali

Just finished replacing the OEM lines with Spieglers. Overall a fairly straightforward job. While the fittings all matched the front top line from the reservoir to the ABS fitting was a quite a bit shorter. I guess that's a good thing. The other lines were all about the same size/length.I used The Fabricator's tip about tying the lever to the grip and left some fluid in the reservoir - close the drain hole, and had very little mess when I removed the lines. I did have a little panic after I replaced the lines and no matter how much I pumped the lever - very slowly with plenty of fluid in the reservoir, I could not build any pressure. I then went ahead and bled the calipers through the bleeding nipples using both MityVac and slow pumping of the lever and kept adding fluid and that (finally) made the lever nice and firm. I think I used almost 2/3 of the brake fluid container and the fluid is now crystal clear. All in all, it took longer than I expected but the job was not particularly difficult evener a novice like me. Thank you all for your valuable input and encouragement. Much appreciated.

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BF204

Glad it went well....mine had 2 little clips on the original rubber line that held the speedo cable and either the clutch (?) or throttle (?) cable... The Spiegler lines are thinner, so those clips don't hold onto the new line. I did a temp / ugly job looping them with black zip ties, but it would've been nice if the kit came with a couple of those cable clips. Forgot to mention that before...

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Lowndes
Fab detailed explanation thank you. I am about to service my front brake calipers (2001 R1150RT) and this gives me enough confidence to do it without forking out for the expensive seal and piston kits. Even starting to think I might split the calipers despite reading warnings that they will warp. Guessing that if I do the four bolts a little bit at a time each, like cylinder heads, to keep the pressure even across the whole thing, it should be OK. Any views on reusing the o-rings here?

 

 

Hey, PatML,

 

I completely disassembled my calipers and reused all the OEM O-rings (one each caliper) and seals. They were pristine, only the brake lines were deteriorating (from the inside) due to TIME, not miles. The seals and O-ring must be better material than the lines.

 

+1 on The Fabricator's post above. The pistons are "pulled back" ever so slightly by the seals.

 

Couple of tips on bleeding - 1) suck the system dry before replacing the lines: MiTyVac. 2) it's easier to push bubbles UP rather than DOWN when refilling the system after replacing the lines. MiTyVac does a good job of this, too. 3) put a couple of wraps of white PVC or Teflon plumbers tape on all the bleed nipple threads before starting. This saves DOT4, paint, plastic, etc, 4) keep a spray bottle full of clean water and several clean and wet shop rags handy. Water neutralizes DOT4 instantly. They are miscible. 5) While bleeding the system BUMP the banjos with a rubber mallet and bump the front forks against the stops to help dislodge tiny bubbles in the fittings. 6) drop a quarter (25¢) in the MC reservoir before starting any of this. It CANNOT seal the ports but will save your dash, plastics, the windshield from DOT4 etching. AMHIK. I just leave 'em in.

 

 

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PatML

Thanks Lowndes. I will get on with it then. Really useful information as ever on this site. MC Reservoir already has a Stanley knife blade in it to prevent DOT4 spraying everywhere. Have a good weekend riding, everyone.

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