Brake master cylinder issues

[KDIMD]

Last week, I changed to sumitomo 6 pot calipers and all was good.

Today, I went ahead and swapped out oe brake lines to galfer lines, the 2 separate cables. I can't get any fluid to the master cylinder using the reverse bleed method. It feels like the banjo bolt at the master cylinder is blocked. If I remove it I can push fluid thru.

What am I doing wrong?

 

[rzwanink]

Do u have the whright banjo bolt. If u want to connect the 2 brakelines to the master cilinder, u will need a longer bolt with 2 (4) holes in it. One for each brakeline

 

[KDIMD]

The galfer lines come with the extended banjo bolt.

 

[rzwanink]

And what if u just bleed it the normal way?

 

[KDIMD]

Tried normal and pumped it for a while
Nothing getting out of the master cylinder.

 

[KDIMD]

I see a new master cylinder goes for $180. Are the other m/c to consider since I am running the 6 pots, such as of a fjr?

How hard are the OEM m/c to rebuild?

 

[KDIMD]

Anyway, have it strapped down for the night.

 

[Traumahawk]

When I changed out the brake lines, (and I didnt reverse bleed, just pumped the lever,) I had to pump the lever probably 50 times, before it would start building pressure, and it STILL took what seemed for forever. I would bleed the brakes, and it would still take 50-100 times of pumping to build pressure. I actually thought I was doing something wrong.....but kept at it. Finally, the lever started getting hard, with fewer pumps, and less and less air was coming out when I bled the brakes.

In the grand scheme of things, the brake MC does NOT displace a lot of fluid, and you are having to displace air (which is compressible) from the entire length of the line. It just might take a bit.

 

[redneksoldier]

^^ this ^^
I recently took my stock masters apart for rebuild and replace sight glass lenses. It took FOREVER to get any pressure back. It was to the point where i was about to take them back apart to see if i jad done something wrong. Keep after it. Just takes a LOT of pumping.

 

[redneksoldier]

^^ this ^^
I recently took my stock masters apart for rebuild and replace sight glass lenses. It took FOREVER to get any pressure back. It was to the point where i was about to take them back apart to see if i jad done something wrong. Keep after it. Just takes a LOT of pumping.

 

[Fire-medic]

I would disassemble all components and ensure you have free-flowing passages. Then reassemble, and as you already did, reverse-bleed. I don't know why anyone would spend all that effort doing a traditional bleed, you can get a 'moving fluid' condition quickly by the reverse-bleed. Even if the system is completely dry, pushing the fluid up from the slave cyl bleeder means when you see the fluid in the master cyl appear, and then start to accumulate, you have pushed most of the air out of the line. When the 'fizzies' stop from the master cyl floor's two holes, the air is gone, and you should have a firm lever. A few 'fans' of actuating the brake lever to equalize pressure on both sides of the brake lever piston and you should be good to go.

Make sure the two holes are clear in the brake master cyl. The front one doesn't take much to block it. You can use a pin to poke-through any crud blocking it. Then make sure it stays open. That's the hole you should expect to see a stream of very small bubbles float out as you continue to reverse-bleed.

 

[KDIMD]

Thanks. I think I have blackage in the m/c cause I can reverse bleed all the way up the line. When I try reattaching the line to the m/c, then no fluid comes out of any holes. I will try to use a pin next.

Is there a chance the galfer banjo bolt for two lines is too long and hitting something? I thought about adding some more crush washers to shim it out a bit.

 

[davesax36]

Thanks. I think I have blackage in the m/c cause I can reverse bleed all the way up the line. When I try reattaching the line to the m/c, then no fluid comes out of any holes. I will try to use a pin next.

Is there a chance the galfer banjo bolt for two lines is too long and hitting something? I thought about adding some more crush washers to shim it out a bit.

Wait. Are you pushing fluid up the line without it attached to the MC?

 

[Fire-medic]

You should be able to stack-up the washers and the hose banjo ends, laying them alongside the banjo bolt and see if the bolt holes align with where the banjo are. If you wanted to, you could assemble the whole thing, and then count the # of turns to remove the bolt. Then thread the bolt in the same # of times into the master cyl, and lay the stack of washers and banjo ends next-to the bolt, and confirm the passageways of the banjo ends align with the holes of the banjo bolts.

All of this really shouldn't be necessary if the system was on the bike before, and worked OK. If the two holes in the master cyl are clear, about the only other thing I can think of is that the inside of one line is internally collapsing. This would usually act as a 1 way valve, allowing you to build pressure, actuating the caliper(s) but not allowing you to release it, until you opened a caliper bleeder. In nearly 50 years of working on cars, bikes, and trucks, I've had this happen twice. Of course, the only solution is to replace the hose.

Thanks. I think I have blackage in the m/c cause I can reverse bleed all the way up the line. When I try reattaching the line to the m/c, then no fluid comes out of any holes. I will try to use a pin next.

Is there a chance the galfer banjo bolt for two lines is too long and hitting something? I thought about adding some more crush washers to shim it out a bit.

 

[KDIMD]

Wait. Are you pushing fluid up the line without it attached to the MC?

Yes, just to test that there is no blockage in the lines before I attach it to the MC.

 

[Fire-medic]

Be sure that you have the master cyl in the position off the bike where the holes in the floor of the master cyl are covered w/brake fluid. If you have them exposed, say when you rest the master cyl on its side, w/the lever facing-up, you'll draw air in when you squeeze the brake lever, probably. Holding the master cyl in a vise w/a couple of thin pieces of wood to protect the finish should allow you to bleed the system to your heart's content.

I've actually assembled the front brake system off the bike, and then installed it onto the bike, but some of the front end components around the handlebars had to be removed.