Brakes real bad.

BadBoy1404 · 09-28-2004, 03:03 AM

Hey i just had a question my brakes have been real bad and feel spongy and almost like the just lack massive friction. And also the brake lever is real notchy. It will go down and stick then jump down and stick and it makes for real interesting stops. Also my rear brake barely works it almost feels like there is no pressure unless I STOMP down on it. I dont think my pads and rotors are that worn. Could it be break fluid? the dip shit b 4 me put in DOT3 instead of DOT4 maybe??? Any suggestions on what to do would help without replacing my entire break system. thanks

dbo · 09-28-2004, 04:12 AM

drain it and replace the fluid...bleed it good.

don't worry too much about the back brake...compared to the front mine have always felt weak...i've never even used the rear brake to be honest!

LifeLiberty · 09-28-2004, 10:43 AM

are the pads worn? dirty? take the pads out and clean the rotor and pad with brake cleaner. did you have a recent fork seal leak and the oil got on the pads, if so, then replace the pads.

replace the brake fluid and make sure no air is in the system. I beleive dot 3 and dot 4 are compatible so i don't think that was the problem. hopefully brake fluid didn't get on the pads either. could be dirt around the piston that is causing it to stick, make sure the seal is n't leaking around the piston. how old are your brake lines, if they are oem, they could be getting spongy with a lot of use. take off your brake lever and clean and lube it.

check for warped rotors also.

jesfz6r · 09-29-2004, 02:28 AM

guys above do have some good points but actually dot 3 and 4 don't mix, your fluid is contaminated and you should replace the hydrualics and hoses on your bikes, ESPECIALLY if they are original, besides when it comes to your brakes why take chances

LifeLiberty · 10-01-2004, 10:47 AM

Actually, 3 and 4 DO mix(glycol-based), but 3 and 4 don't mix with DOT 5, which is silicon based

when you bleed you brakes, use this http://www.valvoline.com/pages/produ...asp?product=51 you can find it at any auto store.

LifeLiberty · 10-01-2004, 10:50 AM

"That leaves DOT 3 and DOT 4 fluids. These fluids are compatible with each other and may be interchanged or mixed with no ill effects. " http://www.shotimes.com/SHO3brakefluid.html

LifeLiberty · 10-01-2004, 10:57 AM

what jes is referring to is this situation when DOT 5 and DOT 4 or 3 are mixed. http://www.belray.com/consumer/Q&A%20pages/q&abf.html

DOT 4 VS. DOT 5 Silicone Coagulation

Q: Sir Tech,
I bought a 1987 Harley-DavidsonÆ Sportster and I recently removed the front brake master cylinder cover to find a bunch of thick gunk inside. What happened and what should I do?

A: If you own a Harley-Davidson®, think purple! Your H-DÆ motorcycle came stock from the factory with DOT 5 silicone brake fluid and part of the regulated requirements for DOT 5 silicone is that it be purple colored so as to stand apart from the ever so popular DOT 3, 4 or 5.1 brake fluids which are glycol not silicone. Apparently, your hog’s previous owner was more concerned with his tattoos turning green than with his brake fluid being purple and most likely added some DOT 3 or DOT 4 brake fluid to the system. This is a big no-no, bad boy! What happens when you introduce DOT 3, DOT 4 or DOT 5.1, all glycol based fluids, to DOT 5 silicone, which is obviously silicone based, is coagulation! The fluid will clot and, as you so eloquently described, form “thick gunk”. My advice to you is to consult a qualified technician. After all these are your brakes we are talking about! Have him fully flush the brake system and replace all the rubber parts with new ones and then go back to DOT 5 silicone brake fluid. If you do not re-build the master cylinders and calipers or replace all the rubber parts, there will most likely be remnants of the glycol in the rubber which will cause the problem again. To avoid "thick gunk" in your shorts due to grabbing the brakes and not impeding forward velocity, I recommend you heed my advice with the utmost seriousness and expedience.

Ghost Rider · 10-05-2004, 10:26 PM

Sounds like you need to bleed the air and old fluid out of your brakes. You could also have a flexable line pinching off when you let off the brakes. This (the flexable hose pinching off under vacuum and stopping the fluid from going back out of the slave cylinders into the master) can cause the brakes to stick on and overheat and possibly warp your rotors and boil you brake fluid.
Edit: Just occurred to me that you should also check that the lever isn't slipping on the shaft if it feels notchy.