WARNING Front Brake Seizing

1055 Views 58 Replies 9 Participants Last post by Mitchell, 4 d ago

Mitchell

Discussion Starter · 26 d ago

My latest experience while riding was a bit scary to say the least. I was glad I wasn't on the highway. After about 30 minutes on the Rune it came to a abrupt stop on its own. The front wheel locked up in the middle of the road. Thanks to a few guys they helped to block traffic. After having the bike towed to the shop we foud that the brake fluid was contaminated so we bleed the brakes cleaning the master cylinder and calipers only for it to happen again. I was expecting it to happen so I was taking it easy when it happened the second time. Upon further inspection in the reservoir there is a valve that allows brake fluid to flow both ways one upon applying the brake and the other on release. We noticed on port on the the valve was secreting cloudy brake fluid and realized the flow of brake fluid was restricted. We have ordered the parts and will update this post when new valve is installed.

If I was traveling at 60-70mph on the highway it could have gone very wrong. If you haven't been changing your brake fluid on a constant basis 3-5k mile I would have the valve change and an bleed the system, clean the calipers etc... My bike was scheduled for a fluid change but it wouldn't have helped the brake fluid was in the system too long.

If your bike slows down by itself it is the caliper overheating and putting pressure on the pads as if you were squeezing the brake handle. Pull to the side ASAP. Once it seizes it takes 20-30 minutes for the system to cool before the front wheel will role. I was in the middle of the street waiting for it to cool. Lucky to have a car behind me blocking traffic.

We are pretty sure it is the valve in the reservoir but will follow-up with this post with the results.

Drive Safe

Mitchell

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21 - 40 of 59 Posts

Mitchell

Discussion Starter · #21 · 14 d ago

Update on Dunlop tire D251. My dealer stated he should have the front tire on June 27th. The rear tire arrived.

We'll see. I'll let you know.

RedValk

· #22 · 14 d ago

Mitchell said:
Update on Dunlop tire D251. My dealer stated he should have the front tire on June 27th. The rear tire arrived.

We'll see. I'll let you know.

Fingers crossed. I also have a front and rear OEM on order. Haven't heard anything......think I'll ping my Dealer today............... Hmmm......June 27th. That would be an excellent birthday "present" if mine came in then. Yes, that's my birthday..............

😁

Mitchell

Discussion Starter · #23 · 14 d ago

What was interesting is my guy at the shop where I ordered them stated he has bunch of front tires coming in on the 27th but he's going to put a special order in anyway. Found that strange. While shopping online I ran across a site that stated "Tire won't ship until Mid June". Maybe it's a sign. Let's hope so.

RUNE~GEARHEAD

· #24 · 14 d ago (Edited)

Mitchell said:
While shopping online I ran across a site that stated "Tire won't ship until Mid June".

What site? Was a price listed? Thanks

RedValk

· #25 · 14 d ago

Just talked to my dealer. He said he saw those same dates.....and then.....it slipped. So no word when the ones I have on order might come in (that includes the rear ....which I also have on order). I could use another model on the rear with the same size, but figure I'll just wait on a rear 251 also.

Mitchell

Discussion Starter · #26 · 14 d ago

RUNE~GEARHEAD said:
What site? Was a price listed? Thanks

Don't remember, I searched everything that showed up in Google. When I saw June I just passed it by. But you can order from where I bought. I believe they ship. If the don't I can pick it up for you and ship it. I bought at Broward Motorsports in Fort Lauderdale, ask for Gabriel M tell him my name Mitchell Pine. He should be able to help. Let me know if you need my help.

Reactions: 1

RUNE~GEARHEAD

· #27 · 14 d ago

"Thanks for the offer, I'm good. Was looking for price to see if it's in line with what some say they will cost."

RedValk

· #28 · 14 d ago

I couldn't find ANY saying in stock OR with any dates.....though one said something about 2-4 weeks maybe. All prices for the front were "hovering" around the 300 mark.....most plus a little....one or two slightly below 300. Of course, NOBODY actually had one....................so no telling what the price will wind up when they actually get one in their hands?

Mitchell

Discussion Starter · #29 · 13 d ago

Soon as I get them I will update the price.

I went to a tire store once and asked the guy for a tire he said it was $250. I said I'll take it he said "I'm sorry I don't have them in stock" so I went down the block to another tire store and the guy said "Yea, I have them in stock,. They're $300. I said the guy down the block is selling them for $250. He asked me "Why didn't you buy them there". I told him he doesn't have them in stock. He replied " Well $250 is my out of stock price also"

MO Rune Rider

· #30 · 13 d ago (Edited)

Hey, I just remembered another brake oddity I had encountered in the past on my 85 Vmax. It's rear brake would start dragging a bit too hard and once even to the point of overheating the disc. I had to pop the rear caliper apart, and on that bike, I had yellow, gooey buildup on the inside of the caliper where the two inner & outer seals sit in grooves. I had cleaned the caliper extensively and reassembled, but reused the same seals. A few months later, the same thing would begin happening. Upon disassembly, the same yellow crude accumulated where the seals install. Recleaned all parts & seals. Same thing a few months later, even though I was using fresh brake fluid changeouts each time. I think the seals were just too old, too soft, too whatever, and allowing the fluid to seep outward too far and gunk everything up. After I cleaned everything a fourth time and INSTALLED NEW OEM seals, (and again new brake fluid) I finally got satisfaction and no more dragging rear brakes.

I think the yellow goo buildup was from the overheating of the brake fluid when the swollen seals would begin dragging the brakes.

I think, also, with just a few miles on the clutch fluid, you are going to see it darken anywhere near the master piston as compared to the bulk, unused fluid up in the reservoir. Also, if brake calipers were clear, you'd see the fluid naturally darkening with normal use near the piston down there as well. Darkening fluid is what is expected during normal operation, and is one of the signs of it needing changed to begin with, but I think the darkening near the master cylinder probably begins about as soon as you start pulling on the clutch lever, vs, being any sign of specific trouble in the system at the master.

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Mitchell

Discussion Starter · #31 · 13 d ago

I learned that lesson the hard way too. Now, once I open it up I rebuild with new parts. New is new. Doesn't pay. The funny thing is once you replace everything and you fix the issue you question yourself "Did I really need the seals?"

The answer is yes. So I remind myself, the seals don't get better with age.

So I am now rebuilding the front Master cylinder on the Rune.

Mitchell

Discussion Starter · #32 · 13 d ago

RUNE~GEARHEAD said:
"Thanks for the offer, I'm good. Was looking for price to see if it's in line with what some say they will cost."

Here's the site I was looking at with a ship date. https://www.summitracing.com/parts/dmp-302550

RUNE~GEARHEAD

· #33 · 13 d ago

Mitchell said:
Here's the site I was looking at with a ship date. https://www.summitracing.com/parts/dmp-302550

"Thanks!

I've used summit racing before for parts, but never looked at them for motorcycle tires. Fair price if it holds for when the new tires are finally available."

AlanSmith7

· #34 · 12 d ago

Ohh !! Thank you so much for sharing this information. This is really a great idea.

Mitchell

Discussion Starter · #35 · 11 d ago

I have an update on the seizing of the front brake. I replaced the valve assembly for the front brake. See attached part. Drained all brake fluid front and back since both systems are attached. I have a higher rear brake pedal now and a whole new feeling with the front brake handle. It seems that front handle travels smoother and brakes have 30% more sensitivity. This brake system is clean.

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Reactions: 2

phat6

· #36 · 11 d ago

Mitchell said:
I have an update on the seizing of the front brake. I replaced the valve assembly for the front brake. See attached part. Drained all brake fluid front and back since both systems are attached. I have a higher rear brake pedal now and a whole new feeling with the front brake handle. It seems that front handle travels smoother and brakes have 30% more sensitivity. This brake system is clean.

Was trying to follow all the different steps and speculation through this thread. What was the actual root cause? Part 46400-MEC-016 was one of the parts / actions you took, or this part was THE root cause? Just looking to understand in unambiguous terms, what exactly caused the lock-up (other than old / bad brake fluid) and needed to be replaced. Thanks. And thanks for posting the issue so fewer of us have to experience the ""Oh, [email protected]#$%^&*!!!"

Reactions: 1

Skip

· #37 · 11 d ago

I've been looking at brown fluid in the front master for a couple of years now. All the talk on here inspired me to flush it.

I sucked out "most" of the brown with a big syringe and put "some" fresh in (never exposing the valve). Then used the syringe again to suck the last of the brown out. I suspect the brown colour was from particulate and it didn't mix with the fresh fluid.
Then flushed until both calipers ran clear. The clutch and rear masters seem clear through the site glass so I'll check them again in a decade or 2...

Thank You http://www.speedbleeder.com/ !!!

skip

Reactions: 1

RUNE~GEARHEAD

· #38 · 10 d ago (Edited)

Skip said:
Thank You http://www.speedbleeder.com/ !!!

RUNE~GEARHEAD said:
Plus: Speedbleeder(s)!"

"Speedbleeder, The SS version/option"

Mitchell said:
See attached part.

"Where did you find a PCV(Part 46400-MEC-016)? All the sites I look @ shows either out of stock or unavailable.

And to tag on to what phat6 posted, what points to the PCV being bad?"

Reactions: 1

AutoRune

· #39 · 10 d ago

I use paper towels to remove the old fluid in the master cyl in fact you stuff a dry towel in and it really leaves every crack and cranny dry

Reactions: 1

Mitchell

Discussion Starter · #40 · 9 d ago

phat6 said:
Was trying to follow all the different steps and speculation through this thread. What was the actual root cause? Part 46400-MEC-016 was one of the parts / actions you took, or this part was THE root cause? Just looking to understand in unambiguous terms, what exactly caused the lock-up (other than old / bad brake fluid) and needed to be replaced. Thanks. And thanks for posting the issue so fewer of us have to experience the ""Oh, [email protected]#$%^&*!!!"

The root cause was contaminated brake fluid which created a buildup and sludge like substance in the reservoir/valve and brake lines. It got to a point that the brake fluid was only flowing towards the caliper and due to the build up in the lines and valve system at the brake handle the fluid backed up creating pressure in the caliper where the brake pads remained on the rotor and overheated causing the the front brake seizure. Immediate remedy is to let it cool down 100% that will give you me 20 minutes depending how much you use the front brake. I decided to tow. I replaced the part described in this thread. That did the trick. Remember your rear brake is tied into your front brake so when you replace the brake fluid do front and back.

Reactions: 2

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