Weak Brakes

AU Bronco · Aug 20, 2007

The previous owner installed the brake booster, as well as disc on the front. I have new pads, calipers, rotors. Master Cylinder is full and brakes are bled. The truck slows fine but i have to stand on it to get it stopped and then it just slow more slowly but not rapidily like it should...i cant lock them up for nothing. The rear drums are junk as to the gear dope leaking onto them from the axle seals....would this cause the problem or is it the mc? The booster works...i think...the pedal depresses when i cut it on and returns when off...also if the engine dies on a hill im screwed...i cant get it stopped till the bottom...adrenaline rush but not very desirable....any help appreciated.

A4x4Junky · Aug 20, 2007

Check to be sure you are getting vacuum to your booster. Sounds like the booster is doing next to nothing.

Anthony

AU Bronco · Aug 20, 2007

ok...ill check...it should be unless the line is clogged bc i have a new engine, intake, and t/a carb on there and when the hose isnt hooked to the carb it runs like crap....where is the check valve on the boost that ive been reading about?

eb66to77 · Aug 20, 2007

What mastercylinder are you running. Could be too big of a bore. I know that when my hydroboost wasn't working on the way to the auto parts store to get a new belt it would slow down slow or fast but I couldn't lock them up.

Apogee · Aug 20, 2007

There should be a check valve at the booster...little plastic thing that the hose attaches to and then presses into a rubber grommet in the booster body. Visit Napa's website, the part number is #UP89000.

Rear brakes are important, but it sounds like your fronts aren't pulling their weight either. Are you running Chevy discs? Have the knuckles been clearanced sufficiently for the calipers? Do you have a firm pedal? If you push on the brake pedal with the engine off, does the pedal sink or raise when you start the engine? If it raises and pushes against you, you've got a bad booster. If is sinks, I'm thinking that your problem is further downline.

AU Bronco · Aug 21, 2007

The master cylinder i assume is stock as i didnt put the power brakes on. The disc are ford...either from a later bronco or off a full width 44 im guessing...dont know i didnt do that either...but i bought calipers pads and rotors for a 76 and they work....the pedal does sink when i turn on the engine. Im thinkink its the mc bc when the truck cuts off i cant stop it for nothing.

AU Bronco · Aug 22, 2007

here is the master cylinder and booster

here is a kink which may be a problem

trailpsycho · Aug 22, 2007

Fix that hard line. Have you tried to bleed the system? Checked the brake fluid? Those would be the first places to look...then check your vacuum at the booster...if its pulling vac, then you may have a bad MC. Its possible that the booster is bad, but I would say its more likely that its the MC. From experience...when/if you need a MC go to NAPA or CarQuest and get a new one, not a reman. I replaced a few remans in the first 2-3 yrs of ownership, then went with a NAPA MC and took it off only for the 'build-up'...will sell with booster once build is complete. The remans often have different sizes or re-tapped holes for the fittings and the last one that was in there left me without brakes (on the way home from NAPA with the new one in Five Points in BHM, AL on a Thursday or friday evening @ ~5pm...rear ended Flava Flav (I was a huge Public Enemy fan and I seriously thought it was Flava, whoever it was had his mom and Grandmother or aunt it the car; it was ugly--the accident.... Right in front of The Mill and I was chastized by folks drinking beer..."why didnt you just shut it down?" and other stupid comments...Flava had a green light but could not decide which of the four remaining streets to turn onto...still embarassing to this day. Anyway, dont trust the cheapo remans. Oh yeah, there was no damage to the Bronco, but the Dodge Stratus (or Plymouth counterpart) had an accordian trunk. Still sucked....I was forced to get my truck towed back to my apartment on my grad school budget.

John

wpaeb · Aug 22, 2007

check that the front brake lines run to the rear of the master. It looks like they are switched. IE rear goes to rear.
Does your peddle go to the floor?

cgbexec · Aug 23, 2007

That large line running from the master cylinder to an adapter doesn't look good. Like WPAEB says, make sure the line connected to the front of master cylinder is going to the rear brakes. If I were you, I would buy new hard lines from the master along with a new master cylinder. Why risk your life over a few bucks.

Chris B.

airman · Aug 23, 2007

I have never seen a 3/8 brake line before. Have you adjusted/inspected the rear brakes?

What size tires are you running? I can't lock up my 35's but I have a proportion valve too. When I have had brake issues it was almost always my rear brakes. CAn you engage your parking brake and hold back the Bronco in gear?

Are you sure its gear oil from the rear wheel and not bad brake cylinder?

I'm not trying to be a jerk at all here but are you sure the front discs are ford and not Chevy? If they are Chevy and not installed correctly they will not stop correctly.

AU Bronco · Aug 23, 2007

ok...ill check the vacum and and the routing of the lines...ill go ahead and replace the lines actually....the lines coming out of the mc go down to a junction...possibly a proportioning valve, on the frame... then from there go to the front and rear breaks...im pretty sure those are ford brakes but just in case how can i tell the difference?.....no on the parking brake i have never used it as the roll cage is in the way.....yea its is gear dope....im sure the kink in the line is a big part of the problem so when i replace that ill let yall know....thanx for all the response

JMP · Aug 23, 2007

ok so I am reading two responses, one says front goes to front brakes, rear to rear. The other says front of MC goes to rear...

What is the correct way ya-all got me cuious?

Josh

Apogee · Aug 23, 2007

JMP said:
ok so I am reading two responses, one says front goes to front brakes, rear to rear. The other says front of MC goes to rear...

What is the correct way ya-all got me cuious?

Josh

It depends on the MC you're using because they come both ways depending on the application, but the MC's used on disc brake EB's have the bigger, rear reservoir to the front brakes and the smaller, front reservoir to the rears. The larger volume is required for disc brakes since the fluid level drops with pad wear.

AU Bronco · Aug 25, 2007

sorry bout the confusion....the rear line coming off the mc goes to the front brakes but it goes to some type of junction(so does the line coming off the front of the mc), possible the prop valve....hope that cleared it up

chuck · Aug 26, 2007

The line nearest the booster MUST feed the front brakes, always. All M/C that will fit this booster must be plumbed that way.
The big line is ugly and should be replaced but that will not fix your brake problem.
It looks like the bracket has been bent to make the M/C set level, if that is the case the bellcrank may not be lining up with the M/C and that is bad, may just be the picture
You may have found the real problem. If you turn off the engine while going down any hill and apply brakes you should have power assist as long as you hold the brake on. From what you typed it seems that is not true in your case which would lead me to believe your check valve is bad or the booster is bad.

Whistler · Aug 27, 2007

AU bronco,

You going to the K-State game?

AU Bronco · Aug 27, 2007

yea thats a big 10-4...im a student so ill be at them all

Weak Brakes

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A4x4Junky

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eb66to77

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Apogee

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