master cylinder replaced can't get fluid to pump through lines?

Question

this is an older winnebago. approx 74/78

Answer 1

Did you pre bleed the master cyclender. If not you will never get it to pump to the lines.
Remove the master and bleed it out
Ill bet you just fillid it with fluid and bolted it on.BLEED IT FIRST
Here is how. First go to the auto parts store and get a bleeder kit.
Next bolt it into a vice and connect the lines to where the fitting go. Now fill the master and route the lines back int the now filled fluid.
Now with a screw driver push in the plunger at the back untill you see no more bubbles.Keep doing this untill all you see fluid
Now bolt it to the Rv and screw the lines on loosly . now while pushing on the break peddle tighten the lines

Answer 2

The thing that stands out is how long have you owned this tank and are you sure that only brake fluid was in the system?

Most common problem would be the rubber hoses to the calipers. No reason but old age and they will swell shut or drip fluid but not squirt fluid when you stand on the brake pedal.

If this has a hydraulic (early age of hydraulic assist was the luxury model cars) assist then the motor would best be running when you step on the pedal to get fluid into the lines.

If anyone every put something like powersteering fluid or transmission fluid in the brake system then all of the rubber hoses and calipers and cylinders would have to be replaced since the effect on the rubber causes it to swell and blocks the line(s).

Otherwise, even if you didn't properly purge the air out of the new master cylinder before connecting the steel brake lines, you should be able to get the fluid flowing by stomping on the pedal a half dozen times and then bleed down each caliper or cylinder one at a time to get the air out of the lines, it should be working.

Occasionally, the vaccum "power brake" booster (the big donut shaped thing you mount the master cylinder on) will get filled up with brake fluid from the old leaky master cylinder and you'd have to replace that booster since you will not be able to force the fluid out with your foot and the whole thing is buggered up.

Good Luck!

Answer 3

You musta got it from Auto Zone. Sorry to hear that good luck.
Take that so called rebuilt master back and get your money back from auto zone and go buy a new one for a few bucks more from napa or car quest or something. Did you bench bleed it? Of course you didn't that's the problem. If you didn't bench bleed that mofo, you will never get chit through the lines. If you dont know how to bench bleed it, at least do it a shade tree way, put the master in a vice or something, open the top, fill it up, and let it sit for about 15 minutes, go drink a beer and smoke a fattie and when it is done, there will be constant fluid out of the two holes where the lines are. You need to make sure the master doesn't empty during this procedure also. Then bolt it up to that hooptie and bleed rr, lr, rf, and lf and you will have brakes good luck and god bless

Answer 4

if you didn't bench bleed it then that is your problem. But not to worry this is an easy fix. Don't take it back off. It should have come with a couple of hoses and some plastic fittings. simply remove the brake lines off of the master cylinder...put the plastic fittings in them holes...do not use a wrench cause it will strip the threads..or gently use a wrench ..then put the hoses on and place the other end of the hoses in the top of the master cylinder with it full of fluid. have someone pump the break pedal while you hold the hoses in the master cylinder resivoir until you have clear fluid coming through the hoses. this should fix your problem. replace the lines and bleed the rest of the system and you'll be up and running in no time.

Answer 5

fill the master with fluid, loosen the bleeder on the wheel cylinder's starting with the longest or farthest away first,usually right rear. then left rear. then right front, and finally driver side. AM sure you know this takes two people,one to loosen the bleeder,the other to pump the brake,when fluid flows solid no air bubbles hold the pedal all the way down,tighten the valve,rep ate in the pre described order, all the time checking the fluid level do not let any air enter!

Answer 6

if you didn't bench bleed the new master cylinder there is a lot of trapped air in the system, try opening up all the bleeders and let it sit all night to gravity bleed the lines.

Answer 7

did you bench bleed it. might have to have it power bled. if that doesn't work the master cylinder may be bad. good luck