Losing brake pressure?

[gunslinger74]

Hi gang, new here, but having a problem. I have a 98 4.0 OHV, I just had the upper control arm and lower ball joints replaced. After having everything put back together, I went to leave the garage. I stepped on the brake to shift to neutral and the pedal sank to the floor. Upon pumping the brakes, I got pressure back again. Started backing the truck out of the garage and starting to turn it around, I stepped on the pedal, and to the floor again. More pumping and pressure returned.

Had my mechanic friend look and he said the pedal felt fine, backed it up and pulled forward about 10 feet and pressure was there. I got back in, pressure was there, pulled out of the lot and started driving down the road. Came to a red light, I had plenty of room, so I started coasting until I needed to slowly and lightly apply the brakes. Again, when I applied the brakes, the pedal sank to the floor. Pumped and pressure came back. Turned around and made it safely to the garage again, but with pressure lost when I applied the brake.

I had no issues that morning when I drove the truck there.

Anyway, up on the lift to look for a leak, and nothing, no leak found. So what do you guys think? Master cylinder, power booster, vacuum leak?

Thanks in advance for any help. I truly appreciate it.

 

[DaExplorer]

Since you say everything was fine before you replaced the control arms and ball joints I would start looking at the lines going to the front calipers. I don't know if you wired them up, let them dangle or took them off. Are you loosing fluid at the master cylinder? If not, then did you take the calipers off? if so when you re installed them did you bleed the fluid to get rid of air bubbles.

Just a place to start looking. Let us know what you discover.

 

[OneLever]

It sounds like you had this work done by a shop right? If the brakes were working fine prior to the job and now their not then they screwed up somewhere. Take it back to the shop and have them fix it. They can't just randomly break stuff while performing jobs and not take responsibility.

 

[gunslinger74]

Since you say everything was fine before you replaced the control arms and ball joints I would start looking at the lines going to the front calipers. I don't know if you wired them up, let them dangle or took them off. Are you loosing fluid at the master cylinder? If not, then did you take the calipers off? if so when you re installed them did you bleed the fluid to get rid of air bubbles.

Just a place to start looking. Let us know what you discover.

It was done at a friends shop. The calipers were hung up, not removed or dangled. Not losing fluid in the master cylinder either.

It sounds like you had this work done by a shop right? If the brakes were working fine prior to the job and now their not then they screwed up somewhere. Take it back to the shop and have them fix it. They can't just randomly break stuff while performing jobs and not take responsibility.

I talked to a couple of friends who are somewhat knowledgeable and they told me it sounds like it might be the master cylinder. it is a 98 and it has 196000'ish miles on it.

I decided to come here, since this forum is all about the explorers and rangers. I explained the situation to several friends, and a couple who are mechanics, and the consensus seems to be master cylinder. I was just curious if anyone here had a similar issue, and if anyone had any advice. I trust these guys, and they did go over and take everything back apart, that came off while doing the ball joints. No leaks were found.

One mechanic at a Ford dealer suggested that, possibly, while compressing the calipers, it may have done something to the master cylinder?

 

[swetrid]

Master cylinder

 

[Fray]

I'm going to have to repeat the master cylinder answer here. The only other possibility that I can think of is a vacuum leak, but since you just did brakes it's extremely likely it's the master cylinder.

 

[gunslinger74]

That's what I was leaning towards. Thanks for the help. Going to replace that hopefully tomorrow.

 

[gunslinger74]

Well, my truck is finally done. It was the master cylinder, as was suggested. Thanks for the info. Now to go pick up the truck tomorrow and get an alignment done next.