Author Topic: No Brake Pressure (Read 4047 times)

KOOL-AID MAN · « **on:** July 30, 2004, 08:37:08 PM »

I just installed a new master brake cylinder (however i did not do a bench bleed and didnt know if i had to) cause the other one was shot. I got the new one in, have the brakes adjusted properly, but it seems i cant get any brake fluid to come out of the bleeding screw in the back, and the front left top nipple (disc brakes in front) i can hear air come out when i open the nipple, but not when pressure is forced on the brakes. duz anyone know what this problem might be?? the pedal goes right to the kickpanel everytime it is pushed in im lost!!

any replies would be great.

Chris · « **Reply #1 on:** July 30, 2004, 08:55:24 PM »

keep adding fluid and keep bleeding them til it comes out, did you drain everything?

KOOL-AID MAN · « **Reply #2 on:** July 30, 2004, 09:21:04 PM »

me and my buddy were doing it for litterally an hour and a half, but nothing came out on some of em, barely could hear the air on some of em, and some of em made no sound or anything, the fluid chamber was full at all times too, i dont get it! it sucks i wanted to go to java hut today

hopefully i'll get it figured out tommorow.

Matt · « **Reply #3 on:** July 30, 2004, 09:39:03 PM »

I had the same problem on a 65 bug a few years back. The car was sitting for a while, and I couldn't for the life of me get fluid to the RR wheel. turns out the rubber brake hose collapsed inside and wouldn't let anything by. Take off the rubber lines and check them for free flowing.

Matt

KOOL-AID MAN · « **Reply #4 on:** July 30, 2004, 09:55:13 PM »

cool, im gonna do that first thing in the morning, hopefully one of my friends feels like gettting up early to help me, haha

James Buchan · « **Reply #5 on:** July 30, 2004, 10:01:42 PM »

same as matt, but what I did was disconnect the two rear lines from the drums, let them hang and kept pumping till the fluid came out - took awhile but worked. It was also after replacing everything - hard lines included.

Chris · « **Reply #6 on:** July 30, 2004, 10:05:01 PM »

yep I agree, sounds like you got some bad lines, is there any resistance at all?

KOOL-AID MAN · « **Reply #7 on:** July 30, 2004, 10:38:42 PM »

there is like no resistance, my brake lines are all copper tho, i dont think there are any rubber ones? i dunno ill have to look at this crap tommorow when it is bright out

Matt · « **Reply #8 on:** July 30, 2004, 10:41:11 PM »

Every wheel should have a rubber hose about 12\" long. they're located between 2 steel lines.

KOOL-AID MAN · « **Reply #9 on:** July 30, 2004, 11:08:08 PM »

ahhhhhhh, ok i will have a look at that, dont recal those really, but im sure they are there :mellow:

Bruce · « **Reply #10 on:** July 31, 2004, 02:38:20 AM »

It sounds to me like you don't have any brake pedal freeplay. If the piston of the MC is slightly depressed when the pedal is on the stop, the port allowing fluid to enter the MC will be blocked. Thus you will never get any fluid at the 4 corners.
To fix this, don't adjust the brake pedal pushrod, but instead adjust the pedal stop bracket on the floor until you have the necessary freeplay.

KOOL-AID MAN · « **Reply #11 on:** July 31, 2004, 11:55:57 AM »

hey bruce, i cant see anything that would resemble a brake pedal stop bracket, can you give me a descritpion of what it looks like, is it on the pushrod? or on the floor. the vw manual doesnt show anything about this.

Bruce · « **Reply #12 on:** July 31, 2004, 01:00:46 PM »

There's a tang on the bottom of the pedal that hangs down below the pivot. Forward of this, hidden by the pedals is a small square bracket about 2\" square that's secured to the floor by a single m8 bolt. Its got a lip that the tang on the bottom of the pedals hit. This is what determines how far the pedals return to when you let off. Get on your knees and stick your head way in there.

KOOL-AID MAN · « **Reply #13 on:** July 31, 2004, 03:28:57 PM »

ok, well, im getting really frusterated so i had to stop werking on it for a bit, im sure the pedal is set up corectly now, and i bought a vaccuum pump to suck the fluid through, i got a bit from the front and then it stopped, ive been going at it for hours, now at all the bleeding screws i got nothing at all, should i take off the master cylinder and bench bleed it and put it back on, is that gonna help me? the 12 inch rubber hoses are all new now, i dont get it. the resevoiur is still topped up as well? maybe i need some new front calpip[ers or something?? i just dont know anymore.

when i bought the car The brakes on the car did lock up at the front when the pedal was almost to the floor, so i know the calipers should still be ok but i dunno, any suggestions?

Matt · « **Reply #14 on:** July 31, 2004, 03:43:08 PM »

The only thing that comes to mind is your doing the bleeding process wrong, or the m/c may be plugged. the m/c was new right? did you check the inlet for crap,?

KOOL-AID MAN · « **Reply #15 on:** July 31, 2004, 04:03:52 PM »

hmmm, i dont think im doing it wrong, it isnt that difficlut to do, i didnt check the inlet to see if it was clogged tho, it is a new master cylinder yes. i think im gonna take it off again and bench bleed it, i really dont want to tho haha, well whatever im gonna get beer and do this!!

Matt · « **Reply #16 on:** July 31, 2004, 05:12:41 PM »

Good idea, I'm gonna get beer too!!

KOOL-AID MAN · « **Reply #17 on:** July 31, 2004, 05:34:14 PM »

nice,. beer is good, well ithe fluid is commin gout of all the outlets, and i still cant get it to the screws, im just gonna wait for my dad to get home, he will figure it out for me :unsure:

Matt · « **Reply #18 on:** July 31, 2004, 07:40:22 PM »

hmmm..wheel cylinders?

Bruce · « **Reply #19 on:** August 01, 2004, 12:04:22 AM »

Quote

, im sure the pedal is set up corectly now,

Do you have freeplay at the master cylinder? If you are not sure, you can remove the brake pushrod completely, then open the bleeder screws and see if fluid dribbles out. If it does, you didn't have any freeplay.
Once you get that sorted out, I'd suggets you gravity bleed the system. What you do is put a hose on each bleeder screw, open them all and walk away. Every half hour top up the reservoir.

KOOL-AID MAN · « **Reply #20 on:** August 01, 2004, 01:47:56 PM »

yeah i got freeplay at the master cylinder for sure bruce, im gonna try your gravity bleeding thing, i guess i should back up on a hill and let the fluid drain out, never dun that before. hopefully it werks

Bruce · « **Reply #21 on:** August 02, 2004, 03:31:22 AM »

You can do it on the flat.
When I had the brake system completely dry on my Mexican car, I tried bleeding it the conventional way. It was getting late so we called it quits for the night. The next morning my Mexican friend opened up all the bleeders and walked away. When I arrived an hour later, it was done.

KOOL-AID MAN · « **Reply #22 on:** August 04, 2004, 10:06:22 PM »

So i found out what was wrong!!! the new master cylinder i bought looked excactly the same on the outside, but the inside had a shorter stroke then the one i took off, it was shorter by half an inch, and not only that but the new one also didnt produce any pressure whatsoever, so i guess it was a bad one right out of the box. Im gonna put the old one back on tommorow. cause i tested it and it seems to be fine. the reason i replaced it was because when i bought the car it had a receipt on it from a brake shop saying it needed a new master cylinder, but it seems fine to me, so im throwing it back in and hopefully it will last me a while, who knows maybe ill throw insurance on before friday so i can race at mission:) thanx for all your help guys, i learned a lot about brakes this past week :lol:

Chris · « **Reply #23 on:** August 04, 2004, 10:13:19 PM »

hey as long as they stop you and the car your pretty mcuh set, and who said anything about needing brakes to go racing?