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pedal is rock hard when engine is off but sinks almost to the floor when started only like 1/8″ -1/4″ til the pedal stops on something hard either pedal or bottomed mastercylinder BUT the thing i is i have brand new front calipers hoses pads rotors and master cylinder i took out the piston from the old M/C and the O-ring seemed fine and pretty sure ive got all the air out ive pressed about 20 fluid ounces of brake fluid though it the system what could be the problem??
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pedal is rock hard when engine is off but sinks almost to the floor when started only like 1/8″ -1/4″ til the pedal stops on something hard either pedal or bottomed mastercylinder BUT the thing i is i have brand new front calipers hoses pads rotors and master cylinder i took out the piston from the old M/C and the O-ring seemed fine and pretty sure ive got all the air out ive pressed about 20 fluid ounces of brake fluid though it the system what could be the problem??
yupp but the brakes were like this before i changed the M/C so obviously my diagnosis was wrong on that
I’ve had this before on some cars especially after extensive brake system work. If it stops ok I would suggest driving carefully on some not so busy roads or a empty parking lot and “bedding in” the braking system. It normally starts building pedal feel. I’m my case normal operation returned after about a 1k km. The brake pads need to compress, master cyclinder and hoses settle, caliper settles. If after that it still behaves badly start looking for leaks sometimes you do get a bad caliper or hose not sealing.
Is it drum in back or disc? Please don’t make duplicate posts.
yeah sorry about the duplicate post it wasnt intentional but its discs in the rear but ive been told by some people with good amount of experience that it could be the brake booster
disconnected the vacuum line and stuck a 1/2″ ratched extender in the hose started engine no pedal difference from when the engine was of pulled extention out of hose and there was a pop as the vacuum was released
pinched off all 4 brake hoses today and the pedal still sank to the floor when i started the engine so i ordere a new booster today if that dont fix the problem its on to the ABS pump
I’m not familiar with the RSX braking system. But it could be a cylinder leaking inside the booster. If you’re going to order a new one anyway, you might try disassembling the booster and checking for that. I’ve seen this same problem in older cars and always found brake fluid in the booster vacuum chamber. Have you noticed if your fluid level is dropping but not finding any leaks?
no drop in brake fluid in the old master cylinder i could notice i wish eric would be available to answer as hes experienced with honda sure brakes are pretty much identical on all cars
[quote=”futten” post=171770]no drop in brake fluid in the old master cylinder i could notice i wish eric would be available to answer as hes experienced with honda sure brakes are pretty much identical on all cars[/quote]
Yeah, it would be nice if Eric could answer everyone’s questions (that would sure help me!). I’m sure modern brake systems are more similar to each other now, but that didn’t use to be the case.
Anyway, I’ve found the causes of issues like these before by disconnecting the brake lines at certain points and closing them off or bypassing them, thereby isolating specific components. You’d need some hydraulic fittings (couplings, plugs, lengths of tubing or hose, etc.) to do that. It’s a lot of work but I’ve needed to do it with older cars where the information just isn’t out there. But, eventually, with a soft pedal, I’ve always ended up finding a leak or air in the system. However, I haven’t worked on ABS much, so that might be another cause I’m not familiar with.
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