Steve Saunders Goldwing Forums banner
Status
Not open for further replies.
1 - 20 of 32 Posts

·
Senior Smart Aleck
Joined
·
1,599 Posts
Discussion Starter · #1 ·
Friend of mine reminded me of his bike accident a few years ago. He was riding along, early spring, first ride of season. Doing about 60 mph all of a sudden front wheel locks up. Bike didn't flip but front wheel kicked out from under it and he went down. 3 broken ribs and a busted collar bone and ego. Someone stopped to help him and they uprighted bike and front wheel was locked up. They suspected wheel bearing but for giggles they released brake bleeder and fluid shot about 10 feet down rode. Took bike to shop for repairs and was telling shop owner about it and the owner said "I know exactly what happened" and proceeded to tell him. What is your best guess as to what happened. I'll finish story on Monday or when someone guesses correct answer.

HINT: Answer is an important annual maintenance task.
 

·
Premium Member
Joined
·
1,822 Posts
My first guess would be some dirty and neglected Brake fluid.. Which should be inspected yearly and replaced every 12K miles or as needed when it is dirty. What do I win, if I am correct???? :lash::lash:
 

·
Senior Smart Aleck
Joined
·
1,599 Posts
Discussion Starter · #3 ·
My first guess would be some dirty and neglected Brake fluid.. Which should be inspected yearly and replaced every 12K miles or as needed when it is dirty. What do I win, if I am correct???? :lash::lash:



:cheers::cheers: This work John?
 

·
Registered
Joined
·
17 Posts
Master cylinder piston stuck forward. Brakes started dragging lightly, building up heat in the wheel calipers/fluid. Fluid expansion applies brakes more heavily, builds up more heat, vicious cycle until brakes lock. Most often encountered with sport bike MCs that have manually adjustable piston depths, from people setting them too far out.

How'd I do?

KeS
 

·
Village Whack Job...
Joined
·
7,908 Posts
Return hole got plugged up. Left pressure in the line causing the caliper to drag creating heat which caused fluid expansion which pushed the piston out enough to lock up the front wheel.
 

·
Premium Member
Joined
·
11,739 Posts
The front brake lever was an aftermarket one and was not letting the piston return completely and the brake stayed on very slightly and as zoom splat has said it bilds up heat and expands the discs and hey presto the bike locks up .
 

·
Senior Member
Joined
·
650 Posts
It could have something to do with the mastercylinder bushing setting up causing the pressure to stay in the system.
 

·
Still Learning
Joined
·
13,274 Posts

·
Premium Member
Joined
·
284 Posts
Dirty slave cylinder, I know it has nothing to do with front brakes, but my first guesses have already been submitted.
 

·
Premium Member
Joined
·
12,868 Posts
ITs very rare and not mentioned yet . Brake hoses can deteriorate internally . IF they start to break down this way they can block flow of fluid like a check valve .
 

·
Still Learning
Joined
·
13,274 Posts
ITs very rare and mentioned yet . Brake hoses can deteriorate internally . IF they start to break down this way they can block flow of fluid like a check valve .
That's another result of lack of PM in changing the DOT4 fluid yearly. Moisture gets in the system and if forms into an acid reaction on the rubber.
 

·
X-Roughneck
Joined
·
1,229 Posts
the shop owner told him there is a new brake fluid out called 'SuperDuperStop 9.9' that is 167 dollars & 92 cents for one cupful that replaces the OLD dot4 Stuff and i told you ,you should have bought it ?


















On a serious note,i hope your friend has since healed well and fixed the problem.What a bad way to go down!
 

·
Premium Member
Joined
·
26 Posts
I think there may have been a buildup of a hard deposit of crud on and around the caliper pistons.This may prevent the piston(s) from fully retacting.Partial brake pressure will still be applied causing a heat buildup that will continue to increase as the bike is driven and the brakes are further applied-eventualy causing a lockup. And or the caliper pins are worn and dirty causing the pads to stick and producing the same result.
 

·
Registered
Joined
·
17 Posts
I think there may have been a buildup of a hard deposit of crud on and around the caliper pistons.This may prevent the piston(s) from fully retacting.Partial brake pressure will still be applied causing a heat buildup that will continue to increase as the bike is driven and the brakes are further applied-eventualy causing a lockup. And or the caliper pins are worn and dirty causing the pads to stick and producing the same result.
That would not do it. As heat built up in your description, there would be no hydraulic pressure to resist the pads retracting - they would just scrape. The heated brake fluid would expand back into the reservoir as normal.

The point of the various suggestions of a clogged line or master cylinder is that it creates a closed system where heat causes hydraulic fluid expansion to push the pads harder and harder into the rotors. That is missing in your scenario.

KeS
 

·
Premium Member
Joined
·
711 Posts
My guess is the owner had done a fluid change during the winter and overfilled the master cylinder
 

·
Premium Member
Joined
·
660 Posts
My first guess would be the pistons were rusty and not able to move back proper and the heat of the pads made the pistons expand thus making them lock up and the return port hole was clogged as well...
 

·
X-Roughneck
Joined
·
1,229 Posts
Yea,c'mon man. Is this a trick question?:popcorn:grab me some popcorn too i guess.
few more hours left or U fall off the CLIFF with ME
 

·
Senior Smart Aleck
Joined
·
1,599 Posts
Discussion Starter · #20 ·
OK So here's what the bike mechanic told the owner. First off, bike was only 2 yrs old.

The mechanic siad that the fluid had drawn moisture and the moisture got to the front caliper. As the bike was ridden the moisture heated up and expanded therefore causing pressure being applied to the brake, just like pulling the brake lever. Enough pressure accumulated that the brake was locked up hence the rider going down. Bike was completely tore down (front brake) and no problems were found with caliper or pins and pads were good.


So who wins the Grand Prize. My best guess would be everyone who responded to this thread because you see the importance of PM.

BTW: Whether you agree or disagree with the above cause, bear in mind that it was not my conclusion. So don't :lash: on me.


So to sum it up, I would say that everyone should change out there fluids annually to err on the safer side. Fluid changing is the last thing I do in early spring just before riding season begins and big temperature changes are over.

In conclusion the rider healed up just fine, but has not ridden since the accident. He says he just can't get comfortable and that little spill comes back to haunt him.

Thanks for the responses, Now get the damn fluids changed :ROFL:


HAPPY NEW YEAR EVERYONE. BE SAFE!!!!
 
1 - 20 of 32 Posts
Status
Not open for further replies.
Top