No brakes after head install

[420a-t]

I installed a new head over the winter with some other goodies, but never touched my brakes. I got everything done and went to drive it around, and my brakes don't stop very well. Over the winter I made sure there was fluid in the reservoir, I've beld them about 10 times in the last 2 weeks. my check valve and my brake booster line is good. I was looking and my vacuum was at 6-8inhg at idle, same as the end of last year but I have no problems spooling up. I did a boost leak test and there was a small leak around the manifold/brake booster area, but I coudn't find it.

My pedal seems fine, it presses down perfect when the car isn't on, but once I turn it on, they go down and feels like they hit the floor. I drive it and press it as hard as I can, and it stops, but it takes a little bit.

I was going to replace my master cylinder, but if I know I'm getting fluid to the brakes, could that still be it? Mabye the brake booster, since my vacuum is so low (no other boost leaks or vacuum leaks.)

Suggestions? I was plannign on going to the track in two weeks but I dunno now...

Thanks

 

[DJYoshaBYD]

Bleed the brakes.. Is your vac line for the brake booster hooked up to the intake manifold?

 

[Mikael SS]

It sounds like, if you did a good job on the bleeding and don't have any leaks, that you should start with the master. It'll still push fluid during bleeding, and if the car stops its able to hold pressure, just not all of the pressure you're applying.

 

[DJYoshaBYD]

ok.. then maybe they werent bled right? Im just offering suggestions.. and why would a head swap make the brakes go out? im just throwing ideas out there...

and a healthy motor should have more like ~16-20 inhg at idle..

so you are not getting enough vacuum or something..

 

[420a-t]

So should I start with removing the master brake cylinder? Would there be any other reasons as to why this would happen? My pedal is fine if the car isn;t on, but once it's on the pedal goes all the way down. I heard that if it does this, then the brake booster is o.k.

Doesn anyone know if a 1g brake cylinder will work on a 2g? Thanks

 

[Mikael SS]

do you know what the brake booster does? All it does is make it easier to push the pedal down. It won't make the car not stop unless you just can't push hard enough.

If the pedal is going all the way down, you have air in the lines (bleed it better), a leak, or a bad master. The only other possibility would be some freak event where a soft line is balloning, but very rare.

 

[vancitydsm]

relax guys his intensions were good.. anyways if you never touched the brake lines and bled the system to infact cure this problem then i would doubt that there is air in the system still. The brake booster assist in applying mechanical pressure to the master cylinder. The equivalent to u using 2 feet and all the force you could on the pedal. So you much understand what going on with and without assist. If the master encounters more pressure the fluid could be simply going around the seals, it wouldn't when the car is off because not enough force. Also you must consider that its easier to compress the air if there is any in the line when your booster is assisting.. I'm a mechanic and this car drove me nuts it seemed to have a squishy pedal and i bled the shit out of it nothing.. changed master nothing. I finally found the culprit and its also something my buddies 2g had a problem with. The slider pin on the the caliper was sized just one of them. So it would actually twist back and forth on the bracket. If i were you i would do a quick glance to look for leaks tick that off the list. Take the tires off and check for caliper float and that it slides back and forth on both pins.. check your rubber hoses but like mike mentioned very rare. If all those check good. Then just replace the master cylinder.. I don't know if the 1g and 2g masters r the same. Probably not..

 

[420a-t]

Ok, thanks for the help and suggestions guys. I'll look at my lines and everything and hopefully everything goes easy! When I replace my master cylinder, isn't there a pin under the dash that I need to remove to take it out? Or can I just remove it from the booster, take the lines off and swap them? Thanks

 

[DJYoshaBYD]

on top of that.. I still wanna know:

Why would a master cylinder go bad during a head swap? That doesnt seem too likely.. There is nothing that you would do to make that go bad during a head swap, unless you beat it with a hammer or something..

I KNOW you have air in your lines.. We just need to figure out where its getting in at (or why its not coming out)

 

[420a-t]

The only thing I did to my brakes at all is when I did the swapp I had to make the lines shorter going from the reservoir to the master cylinder. I thought those might be leaking, so I replaced them a couple days ago, beld the brakes AGAIN, and still the same thing. I ordered a master cylinder today and should be here on friday. Hopefully that cures the problem.

 

[DJYoshaBYD]

how exactly are you bleeding the brakes? are you working from the caliper farthest away from the master cylinder?

Please post EXACTLY how you are bleeding your brakes, because it would be a shame to have you put on (and ruin the chance of refunding it) the master cylinder, only to find out that you still have air in the lines from not bleeding them correctly.. Im not saying you are incompetent or anything like that, but you may be doing something incorrectly...

 

[420a-t]

No, I understand. It would save me a lot of money too...

The first couple times I did them I started at the furthest away wheel and worked my way closer to the master cylinder. I had a buddy in the drivers seat, and him saying "1...2...3!" and on three, he pushed down on the pedal as hard as he could, and I opened teh bleeder valve only for a second, enough to see that my coke bottle was filling up with fluid. He then held the brake down to the floor until I yelled "OK" only then could he release the brake pedal from the floor. I made sure my reservoir was full the whole time too.

The last times was the same concept, except that my friend pumped the brakes 4 times. Each time he said "1...2...3...4...go!" He pushed on the brakes at every number and "go". On go, I then opened the bleeder valve and closed it asap.

everytime I did this, I filled my coke bottle up to the wrapper (1/2 way up). Only then did I proceed to the next wheel, only to find my hard work did nothing for me. If this is wrong please tell me, so I could save some money and not replacing something that is working perfectly fine. Thanks

 

[Defiant]

Pay a shop to do a power bleed on your brakes before you waste any more time. Your method doesn't sound very effective.

And children, watch yourselves.

 

[DJYoshaBYD]

Really, you have the basic concept right.. You shouldnt have a problem with it, but when you open the valve, does it spit like an empty aerosol can, or does it shoot a solid stream of fluid? You can really only move to the next wheel after you you ZERO air.. As bad as they could be, you may have to bleed them multiple times before moving on to the next wheel to get all that air out.. I highly doubt its your master cylinder.. Get your brakes bled by a pro, or try this:

How to bleed brakes

 

[420a-t]

Thanks for the link. When I open the valve, It shoots more of a solid stream of fluid too, but not very powerful at all.

 

[DJYoshaBYD]

It sounds like you need to bleed the living shi+ out of them.. .. follow that.. really, you bleed the brakes until the pedal gets stiff, then bleed some more.. you have ALOT of brake line to get air out of, and it doesnt go at too fast a pace, simply because you are only moving about 1 inch worth of fluid/air in the lines out every time you open the valve.. Its just takes time, especially when you have that much air in the lines.. Bleeding should fix it, as you did NOTHING to make anything else go bad.. Like I said, short of beating the master cylinder with a hammer, there is nothing you would have done during a head swap that would make that piece of equipment go bad.. Unless you are like gambit, and you touched it and it blew up? haha

 

[Carmenpzito]

try bleeding them until you pass 1 quart of fluid through the system. you got air in the lines when you replaced them and, correct me if im wrong, but if they were before the proportioning valve the air would be split up to all corners. make sure you circulate the fluid completely.

 

[DJYoshaBYD]

try bleeding them until you pass 1 quart of fluid through the system. you got air in the lines when you replaced them and, correct me if im wrong, but if they were before the proportioning valve the air would be split up to all corners. make sure you circulate the fluid completely.

YOUR WRONG!!!!!!


Just kidding.. Very right, my friend..

Bleed the SHI+ out of them