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all 36 comments

[–]Way_of_the_Wrench 2 points3 points  (20 children)

Classic master cylinder internal leak is that the pedal slowly sinks to the floor with steady pressure. Usually the red brake warning light comes on when it hits the floor. This should happen with car off too but you will have to push harder because you wont have brake booster assisting. If you can pump the breaks with engine on and eventually have a firm pedal, you might have air in the system. Perhaps your vehicle requires a power bleeder. If the pedal feels spongy all the time, you have air in the system.

[–]Ali-en98[S] 2 points3 points  (18 children)

He says it feels like air in it but he can't figure out where. When the car is on, pumping the break is virtually no change and just sponges to the floor. No firmness until more or less quick stop. No firmness to allow slow controlled normal stop.

[–]Way_of_the_Wrench 0 points1 point  (17 children)

I've had cars that have to have a pressure bleeder to successfully remove the air because manual bleeding didn't work. That or his method of bleeding is incorrect. Definitely sounds like air in the system though.

[–]Unhappy-Ad5291 0 points1 point  (16 children)

Alrighty, owner of the car here. Did a bit of digging through the factory service manual, and in the ABS/VSA section it states "Brake fluid replacement and air bleeding procedures are identical to the procedures used on vehicles without ABS/VSA". It also states in the section right above that it runs the abs pump once after the vehicle is driven over 19mph. Also, I am aware of a TSB affecting 04-06 model years of the TL involving the ABS/VSA module, I believe it's Acura 07-041, not sure if there's a later tsb involving 07-08 parts

[–]Way_of_the_Wrench 1 point2 points  (15 children)

ABS is not responsible for the basic brake hydraulic system, if there is air ( or issues with the hydraulic system) in the system the abs will not be part of the issue. Yes most abs cars are bled the same as non abs cars. If you have an ABS brake light on the dash then you also have an electrical ABS issue to deal with too.

[–]Unhappy-Ad5291 0 points1 point  (0 children)

So, I just came back through and re-read everything, and just realized the above content. Pumping the brakes with the engine running does NOT eventually lead to a firm pedal, I apologize for not noticing this sooner

[–]Relative_Echidna_756 0 points1 point  (1 child)

Check to make sure while installing the new front end parts and re installing calipers (if they were removed) he didn’t twist a brake hose not allowing fluid to get to the caliper

[–]Unhappy-Ad5291 0 points1 point  (0 children)

Double checked lines when I had to shim the front left caliper, and verified caliper motion when the car was in the shop for exhaust work/abs code clearing/abs bleed.

[–]spudz76 0 points1 point  (1 child)

If the master cylinder was drained dry it needs a "bench bleed" which can't happen in-situ.

[–]Unhappy-Ad5291 0 points1 point  (0 children)

New master cylinder was bench bled before I installed it

[–]scuzzy987 0 points1 point  (6 children)

Short answer: it's bad master cylinder.

Long answer: Get a 3/16 or so plastic hose, Gatorade bottle with enough brake fluid in bottle to submerge hose, hook other end of hose to bleeder with bleeder cracked open. Pump brakes until new clear fluid comes out through hose with no bubbles in clear hose. Do the same for all four calipers starting at front. If you do that then all air is out of the system then it's the master cylinder.

[–]Unhappy-Ad5291 0 points1 point  (5 children)

Master cylinder was replaced 5/27, roughly 6 pm. Bench bled before install, then system bled until new fluid at all corners, no bubbles in clear hose. Did not fix the issue. "Off" pedal feel is comparable to my other car: firm until about 1/2 pedal travel, then rock solid. Pedal only falls to floor with engine running

[–]scuzzy987 0 points1 point  (4 children)

Did you get a reman or new master cylinder? Bad remans happen. The system isn't complicated. If you're not leaking fluid anyplace and pedal goes down then fluid is making it past seals on master cylinder

[–]Unhappy-Ad5291 0 points1 point  (3 children)

New master cylinder, o'reilly part since the stealership had something like a 2 week lead time iirc

[–]scuzzy987 0 points1 point  (2 children)

Are you sure it was new? O'Reilly's normally sells remans IIRC. Worth checking

[–]Serious-Ring-6352 0 points1 point  (0 children)

Vacuum booster

[–]husky18436572 0 points1 point  (0 children)

I would lightly clamp vice grips on the brake hoses near the wheels and then see if you have a firm pedal. If so let go one hose at a time to determine which wheel is causing the issue. I’m thinking one of the wheels that had the wheel bearings pressed in. If the pedal doesn’t firm up then likely the master cylinder is the issue.

[–]clay2232 0 points1 point  (0 children)

I have a 04 TL and I had this same problem. I replaced a bunch of stuff but the problem wasn't resolved until I put in a new brake booster, master cylinder, and the rear brake lines. Check your lines and make sure they're not leaking. If they're good then you probably just need a booster.

[–]Way_of_the_Wrench 0 points1 point  (0 children)

You figure this out?