Bleeding after new lines

Hi all, 96 1100RT, just replaced the brake lines, time to bleed. Do I need to bleed at the ABS block and calipers or just at the calipers? Dave

It is better to bleed both.

I did the brake lines on my '99 RT a few years back and did bleed at the ABS block. Used plenty of brake fluid and a mighty vac and was rewarded with an air free system.

I amortized the pain of pulling the fuel tank by throwing in an R&R of the fuel filter.

It may be better, but not required.

You can do the calipers only but use a Mity Van type devote or a suction/vacuume type bleeder , NOT the pump pump method on a bike that age.

I also like D.R.'S method of going down a dirt road and carfully engaging the ABS a few times to "rotate out" some of the fluid out of the modalator then bleeding again .

Yeah I have a Mityvac, plan to use it. Seems like it always sucks air (I guess) between the threads of the bleeder nipple. Like I always get a long consistent string of little bubbles.

Maybe that's ok as long as I also get bubbles out of the actual brake lines. I've tried the grease trick, kinda messy and a pita... Dave

Yeah I have a Mityvac, plan to use it. Seems like it always sucks air (I guess) between the threads of the bleeder nipple. Like I always get a long consistent string of little bubbles.

 

Maybe that's ok as long as I also get bubbles out of the actual brake lines. I've tried the grease trick, kinda messy and a pita... Dave

Morning Dave

If you use a vacuum type bleeding then you will definitely have to bleed the top fittings on the ABS controller as vacuum bleeding doesn't move enough volume of fluid fast enough to purge the air out of the high spots.

Think of a garden hose laying out on the ground with high & low spots. Now pour some water into that hose then stick the inlet end of the hose into a bucket of water. That hose will have remaining air in the high spots & have air on top of the water even in some of the level spots.

Now hook up a vacuum to the outlet end of that hose & start pulling a vacuum on the hose, the vacuum will slowly just keep pulling a small flow of water from the bucket slowly through that hose & the new water will slowly flow under the high trapped air & leave most of that air in place.

Now, same hose, same high & low spots. Hook the hose inlet to a forceful water supply (like a faucet) then turn that faucet on & off a few times. That will hit the inlet end of that hose with a full diameter flow of water, at volume, & under pressure. That quick moving full diameter slug of fluid will force it's way the full length of that hose pushing the old water & any air out the inlet.

If you want ALL the air out of a system that starts out full of air then bleed it by forcefully pumping the brake pedal or lever. The got-ya on this is on older brake systems it can allow the master cylinder piston cups to run full length in a curded up cylinder & cause leakage past the piston cup. But, if you have a system with a curded up master cylinder bore it should be taken apart & cleaned anyhow as sooner of later you will use the brakes with enough force to push the master cylinder piston there anyhow.

DR- Well I have a master cylinder rebuild kit, just need to take that MC off, clean her out and rebuild it. Should've done it last weekend. Guess I was in denial as the brakes work fine with no leaks.

So should I use the MityVac to start it off and finish the job with an old fashioned pedal / lever pump pump bleed? Would the ABS block be bled with the Mity or with a pump pump bleed? Dave

DR- Well I have a master cylinder rebuild kit, just need to take that MC off, clean her out and rebuild it. Should've done it last weekend. Guess I was in denial as the brakes work fine with no leaks.

 

So should I use the MityVac to start it off and finish the job with an old fashioned pedal / lever pump pump bleed? Would the ABS block be bled with the Mity or with a pump pump bleed? Dave

 

Evening Dave

Personally I'm not a big fan of using a MityVac for brake bleeding, especially starting on an empty system.

Using a hand vacuum source just doesn't move enough fluid fast enough to pick up & remove hidden air in the high spots.

MityVac would probably be sufficient for maintenance type fluid replenishment if starting with an air free system but is a pain in trying to restore an empty system back to an air-free system.

With a vacuum type bleeding you are trying to pull air & fluid DOWN & out the caliper bleeders, problem is the air wants to go UP on the fluid so unless you can move big slugs of full diameter fluid then the air can slip by & just go back up.

For vacuum bleeding to be most effective the fluid supply/source should go in at the calipers & be sucked UP & out through the master cylinder reservoir. That way the fluid wants to carry the air up with it.

Using the brake lever or pedal allows big slugs of fluid to be pushed through fast with force pushing the air out with the fluid.

DR- ok, sounds like you recommend the old school pumping method. I'm pretty old school so that fits.

So at the ABS block I would pump and bleed just like at the calipers, right? There are 2 ports, Is one is for the front and one is for the back or are both ports for the front?

As far as the front rebuild kit goes, the "kit" I have has a boot, 2 little copper washers (for the banjo) and 2 rubber seals. I guess these 2 rubber seals go on either end of the piston. My kit did not include a piston. Never found a rear rebuild kit.

And it looks like the whole assembly doesn't need to come off the handlebars. That's good. Dave

DR- ok, sounds like you recommend the old school pumping method. I'm pretty old school so that fits.

 

So at the ABS block I would pump and bleed just like at the calipers, right? There are 2 ports, Is one is for the front and one is for the back or are both ports for the front?

 

As far as the front rebuild kit goes, the "kit" I have has a boot, 2 little copper washers (for the banjo) and 2 rubber seals. I guess these 2 rubber seals go on either end of the piston. My kit did not include a piston. Never found a rear rebuild kit.

 

And it looks like the whole assembly doesn't need to come off the handlebars. That's good. Dave

Evening Dave

Personally I usually start with the master cylinder & get the air out of that first (If you don't you will be pushing air into the system as you try to bleed).

Once the master cylinder is fairly air free then bleed at the ABS fitting, then at the calipers, or just do the calipers.

Then go back & re-bleed at the ABS fitting again.

I like to stop once I have most of the air out, then close all bleeders, then squeeze the lever hard, or push the pedal hard, then allow fingers to slip off the lever, or let foot slip off the pedal, as that compresses the air bubbles & gives the standing fluid a reverse pulse that dislodges trapped air (I do this a couple of times). Then do a quick re-bleed at the ABS fitting & calipers.

Then, if I have the time, or if I still don't have a firm air free pedal or lever, I ride the bike on a dirt or gravel road & get it into an ABS event on front & rear brake. Then return to shop & re-bleed at the ABS fitting & calipers.

Sometimes it is super easy & quick to get all the air out & other times it can test your spirit.

If you start with an air free master cylinder it usually goes pretty easily.

The ABS-2 system is pretty easy to bleed. But, look at the lines of the front compared to the rear. The ABS module is the highest spot in the rear system. It's very difficult to get fluid to pump through the rear line when the lines are empty.

Open the reservoir and the caliper bleed screw, then fill a syringe or a bleed bag with brake fluid and connect a hose to the caliper bleed screw. Push fluid into the caliper and in short order you will see fluid filling up the reservoir. Once the reservoir has fluid, then you can remove the syringe from the caliper and then bleed again by pumping the brake pedal and getting fluid out of the caliper bleed screw.

DR - thanks for you advice.

How do I get the air out of the Masters?

Do I pump bleed out of the ABS block nipples, or use the MityVac on the ABS nipples?

Dave

DR - thanks for you advice.

 

How do I get the air out of the Masters?

 

Dave

Dave - look at your front circuit on the R1100RT. Your master cylinder is the highest spot. Open the MC at the handlebar, fill it with brake fluid and then attach a bleed bag or catch basin to the caliper bleed screw. Open the caliper bleed screw and watch the fluid level in the MC and wait ...... and wait .... it will gravity feed down the entire circuit, just keep adding fluid to the MC as the level drops. If you want to move it along faster, you can pump the lever - gently - which will push the fluid down the hoses faster. It is really that simple.

With empty lines, you can't do this on the rear circuit - because the MC is lower than the ABS module and the fluid won't flow uphill. Reverse fill from the caliper until the MC is filled with brake fluid.

DR - thanks for you advice.

 

How do I get the air out of the Masters?

 

Do I pump bleed out of the ABS block nipples, or use the MityVac on the ABS nipples?

 

Dave

Morning Dave

Do the ABS & caliper bleed nipples last, you first need to get the air out of the master cylinder. If you just fill the master cylinder reservoir then start pumping, or just allow the fluid to run down using gravity you will get fluid under the master cylinder but still have a LOT or air trapped above the fluid & in the master cylinder area.

On the front brakes, start by filling the master cylinder reservoir about 3/4 full of fluid (ABS & caliper bleeders closed), then move the front lever in & out slowly about 1/8 to 1/4 stroke. Look into the bottom of the reservoir at the little take-up port hole in the bottom. (make sure to keep the reservoir fluid level at least 1/2 full but not fully topped off)

You should see air bubbles coming out of that take-up port hole as you move the brake lever in & out the 1/8-1/4 stroke. It also helps to turn the handlebars so the master cylinder is high then low then high again. Don't move the brake lever fast enough to get a big squirt of fluid up out of the take-up port hole or you can squirt fluid on the bike's paint (you should have a plastic garbage bag & newspapers under the master cylinder area anyhow so you don't get brake fluid on you paint & dash plastic).

Once the air bubbles stop coming out of that take-up port hole you can then bleed at the calipers & ABS bleed nipple using full stroke on the hand lever.

Do the same on the rear but you won't be able to see the air bubbles coming back up so just do it by feel (short strokes on the pedal to begin with). The rear usually bleeds out pretty easily as you need to push the fluid up into the ABS unit so the air naturally wants to go up with the fluid column where you can bleed it out at the ABS bleeder.

DR, great. Thanks for the step by step. I'll get going on that MC rebuild tonight and do my bleed. Currently all of my front bodywork is off, even the front fender. Thought I'd leave it off till I got this bleed done. Dave

DR, well I did the master cylinder rebuild tonight, boy are those seals tight!

When I took the MC apart, I took the lever and floppy little plunger off together. I don't see how to assemble the plunger to that boot. If I push it in, it collapses the boot. That locktited pivot pin is really tight, does it need to come off to reassemble with the boot properly attached? Thanks again, Dave

So we bled today. baby we bled!! DR I followed your advice, started with getting air out of the MC. The whole process took a while but I think it feels pretty firm. and of course I let the res get too low (both front and rear- dammit) so I had to back up and do it again.

I used a rotating combination of the pump 5x, hold, quick open technique and MityVac. ABS, Left bleeder, right bleeder, repeat. The fluid coming out of the back ABS port at first was quite dark. yikes!

I wonder how much travel the front brake lever should have before braking is felt. it seems like there is pretty much travel to me. but this is the only oilhead I've ever driven, no point of reference.

I think I used half a roll of paper towels today! Dave