Brake problem on a 47

H

harvsfl

Member
Replaced a front cylinder, bled the cylinder and filled the master cylinder. Pumped the pedal a few times and bubbles came up from the bottom of the cylinder and now the pedal won’t go down. And the brake shoes are now dragging. What has happened?
 
Your brake rod going into the master cyl is not adjusted right. It must have some free play before it pushes the cyl. About 1/8in. Walt
 
Walt is 100% correct about the rod needing to be properly adjusted.
I do have to ask, "Were the brakes operating okay before you changed the front wheel cylinder?" That is, other than the wheel cylinder being defective...
If the brakes were okay (except the wheel cylinder) and now you are getting a hard pedal, I'd bet some type of contamination got into the master cylinder and is plugging one or both of the ports at the bottom of the master cylinder.
Did you allow the master cylinder reservoir to go dry before refilling?
 
Yes the brakes were working good when I found a leaking cylinder. I beleive the master cylinder ran dry as I was bleeding the wheel cylinder. I am stumped. Will adjust the push rod, but first will wait for a reply to this post.
 
harvsfl said:
Yes the brakes were working good when I found a leaking cylinder. I beleive the master cylinder ran dry as I was bleeding the wheel cylinder. I am stumped. Will adjust the push rod, but first will wait for a reply to this post.
Click to expand...
If it was working before, and NOW you have a hard pedal something (debris) must have got in to the master cylinder. There are two ports at the bottom of the reservoir. they must be OPEN. One is about 1/16" diameter. the other perhaps half that, 1/32".
No need to adjust the rod as it was working before. Look for something you changed... Are all wheels locking up or only the wheel you worked on? If it's ONLY the wheel you worked on, either a defective cylinder and or/ hose at that wheel. Did it bleed okay?
If ALL four wheels are locking up, then it is most certainly at the master.
You can IM me if you like and I'll help you through this step by step. My first advice is see if all wheels are locking up or only the one. That way you know what direction you must go in to repair.
 
It is the wheel with the new cylinder. The other front wheel is OK. The cylinder did bleed OK as I had about 1/2 cup of fluid in the can.
The pedal is a little softer this morning but still right at the top.. Replaced the cylinder last Saturday.
 
I don't know how the brake shoes adjust, but they could be out too far locking the drum. Just a thought.
 
Okay, You are in fact getting a hard pedal... by that I take it the pedal pumps up and stays up for a time.
Also, the only wheel holding up is the front wheel that you worked on.
If I understand the above correctly, the problem is obviously at that wheel.
The hose could have been damaged and / or the wheel cylinder is defective.
That could be a couple of things... the pistons are not set well in their bores (IE cocked and / or too loose) or the hole that allows the fluid to go in and out of the cylinder is covered by debris.
I would at this time remove the wheel cylinder and inspect it very closely. One place or another the fluid is not being allowed to return from that cylinder at the rate that is necessary.

Questions:
Is the hose at that wheel new? If not, how old?
Wheel cylinder: Remanufactured? New?
 
Pull the wheel off of the one that is dragging and see if you replaced everything correctly. Compare it to the other wheel. It sounds like when you pumped up the brakes something jammed. Good Luck.
 
I want to thank everyone for their suggestions. Turns out the ancient hose was damaged in the repair process. Replaced hose and all is well.
Harvs
 
harvsfl said:
Yes the brakes were working good when I found a leaking cylinder. I beleive the master cylinder ran dry as I was bleeding the wheel cylinder. I am stumped. Will adjust the push rod, but first will wait for a reply to this post.
Click to expand...
did you fill the mc before trying bleed the wheelcylinder hope so.
 
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