Seriously ANOTHER brake master cylinder???

[Baddecision93]

Ok, got a call from Ford today...It seems everytime I touch brakes I end up needing a new master cylinder. Am I doing something wrong or does Ford just need a new fridge in their break room?

I owned a '00 Mounty, replaced pads and rotors, and couldn't get brakes bled. I had (in my ignorance) unhooked the calipers to squeeze them out to get the pads in. So maybe that one was my fault, and I went to Ford to pay for a power bleed. Got a call saying I needed a new master cylinder...Ok, there went $150.

Now my 1992 Explorer goes in to get the brakes power bled (got a hole in a line doing my lift so had to replace a section of brakeline and couldn't get the rear bled right) and they just called - evidently it needs a new master cylinder. Another $150 .

Two brake jobs in a row, two master cylinders in a row...What am I doing wrong???

 

[DV8]

what are you doing wrong? power bleeding, and blowing the o rings in the master cylinder

 

[Baddecision93]

what are you doing wrong? power bleeding, and blowing the o rings in the master cylinder

I only manually bleed the brakes; just at the bleeder nipple. But I couldn't get enough firmness so I took it to Ford to let them power bleed it. Are you saying that they are blowing the O rings when they do that?

 

[92exp4x4]

Your 92 can be conventionally bled. The 93-up have 4 wheel anti lock. There is a pump motor that must run while bleeding to bleed the valve body of air. This is what I understand power bleeding to be, i could be wrong.

What is the 'power bleed' procedure they are using. You can force fluid using low pressure air or use vacuum at the wheels, but these should not be needed on your 92.

 

[Baddecision93]

Your 92 can be conventionally bled. The 93-up have 4 wheel anti lock. There is a pump motor that must run while bleeding to bleed the valve body of air. This is what I understand power bleeding to be, i could be wrong.

What is the 'power bleed' procedure they are using. You can force fluid using low pressure air or use vacuum at the wheels, but these should not be needed on your 92.

I tried to just conventionally bleed it at the nipple.
Maybe on my '00 Mounty the 4 wheel ABS is why they needed to power bleed but to tell you the truth I'm not entirely sure which process they use.

All I know is conventionally bleeding I was able to get (what I thought was) all the air out and I still didn't have as much pedal pressure as before doing brakes. When I called both a non-dealer shop and the Ford service department they both told me I needed to come in and have it machine bled. They said this just from the lack of firmness symptoms I described to them.
And when I went in both times now I was told that they tried to power bleed and it didn't work because I needed a new master cylinder. Maybe both vehicles were just old enough to need it but if I'm doing something wrong when I'm changing brakes I'd like to know so I don't spend an extra $150 every time I do brakes.

 

[92exp4x4]

I totally understand what you are saying. That gets pretty expensive, fast. I would say you did nothing wrong while bleeding, but I was not there to see your method. Most likely it is coinsidence that both went bad.

I have never had problems with a master going bad when re doing the brakes. The last job i did was on my 94. Literally everything but the master was replaced. I had a soft pedal for the first couple miles then it sorted itself out. Now about 400 miles later it has the proper feel and feels the same as my other trucks. I removed the ABS completely from the truck so it is now a textbook example of a conventional brake system. This one will be used mostly for off road.

 

[Baddecision93]

I totally understand what you are saying. That gets pretty expensive, fast. I would say you did nothing wrong while bleeding, but I was not there to see your method. Most likely it is coinsidence that both went bad.

I have never had problems with a master going bad when re doing the brakes. The last job i did was on my 94. Literally everything but the master was replaced. I had a soft pedal for the first couple miles then it sorted itself out. Now about 400 miles later it has the proper feel and feels the same as my other trucks. I removed the ABS completely from the truck so it is now a textbook example of a conventional brake system. This one will be used mostly for off road.

I was reading in my Haynes manual that if air gets into the hydraulic control unit (HCU) that the brakes have to be bled on a special machine. On the Mounty I can see where that would've happened, since in my inexperience I disconnected the calipers.

However, I've learned from my mistakes on the Explorer and while the rear lines into the drum were disconnected for a short period I didn't let enough air in for it to be a problem (in my opinion).

When you say your brakes "sorted themselves out" I think I know what you mean. I was disappointed in the lack of firmness after I got my truck back from Ford and my dad said that systems "self-bleed" to a certain extent. I have noticed now with a few days of driving that I am actually getting more firmness back.

Maybe you are right and it's just age. I can live with that. I just hope that next time I do brakes they don't say I need another. Just wanted to make sure I wasn't doing anything blatantly wrong, you know?

 

[69Explorer69]

Sounds to me you are doing everything by the book..Like bad said i think it was just a coinsidence that they both went.

I would be like wtf is going on if it happened to me..i would most likely think it was something i did if it happened to me...I have no luck when it comes to car issues.For example last week i was hearing metal to metal so i found a bad tie rod and replaced it..no more then 3 hours later my brakes start to grind,the nexted day,my water pump went,no when i start it i can hear the starter getting weak,went to go to the store last night and smelled a faint smell of wire burning guess what my headlight switch went bad now i have no dash and ac/heat backlights...

THis has been going on for going on 2 weeks its sucks...I replace one thing and something else breaks hours later..its a losing battle for me..trying to keep my head up high so i dont have to part from HER

 

[Baddecision93]

Sounds to me you are doing everything by the book..Like bad said i think it was just a coinsidence that they both went.

I would be like wtf is going on if it happened to me..i would most likely think it was something i did if it happened to me...I have no luck when it comes to car issues.For example last week i was hearing metal to metal so i found a bad tie rod and replaced it..no more then 3 hours later my brakes start to grind,the nexted day,my water pump went,no when i start it i can hear the starter getting weak,went to go to the store last night and smelled a faint smell of wire burning guess what my headlight switch went bad now i have no dash and ac/heat backlights...

THis has been going on for going on 2 weeks its sucks...I replace one thing and something else breaks hours later..its a losing battle for me..trying to keep my head up high so i dont have to part from HER

Well I hope you're right...

Sorry to hear about your bad luck . I seem to have the same problems with Fords but I just love them too much to buy anything different lol. It's a very dysfunctional relationship.
I think on these you just plan to continually put parts on and once you get to the end you can replace whatever you put on in the beginning.
Owning a car is a catch 22 I think...You can buy a new car and have a payment and you don't have to worry about repairs (usually) or you can get something older like this and spend a car payment's worth of money every month on repairs...Either way, you're going to pay.
Or, if you're the kind of person who can pay cash for a brand new car, well I officially hate you and you don't have to worry about a car payment or repairs and you make much, much more money than I.

 

[69Explorer69]

yea sounds about right to me..but i love my X and wouldnt trade her for nothin else (well maybe for a new one lol).gotta love fords...but i really can complain bec since i have had my X i have had a 96 neon with 92,000 and i blew up the PCm(onboard computer)..got rid of that to get a 2004 grand prix..drove it for 2 weeks and the head gasket went bad,replaced new head and gasket.What i am tryingt o get at is when having all these problems,My X has never let me down YET!

Gotta Love Em..Hope you have better luck with master cylinder then i do with having new problems come up as soon as i fix the last one

 

[runderwo]

Just a few things. Excessive pedal travel while bleeding an old MC can waste the seals by scraping against corrosion/gunk. But it shouldn't kill it immediately. Another thing that can happen is you replace old waterlogged brake fluid with new brake fluid, which leaches the water out of the swollen MC seals and shrinks them, causing a dropping pedal. But again this would happen over time, not immediately. The final thing that comes to mind is that you have air in the RABS unit or a stuck dump valve that is letting brake fluid into the reservoir inappropriately. I have an intermittent low pedal on my 91 because of this. I have no idea about those power bleed machines but I have manually bled my 91 so it is not necessary to power bleed. It was a PITA when I had to replace the broke front to rear brake line and the master cylinder, there was air in everything, but eventually I got it all out.

 

[Baddecision93]

Just a few things. Excessive pedal travel while bleeding an old MC can waste the seals by scraping against corrosion/gunk. But it shouldn't kill it immediately. Another thing that can happen is you replace old waterlogged brake fluid with new brake fluid, which leaches the water out of the swollen MC seals and shrinks them, causing a dropping pedal. But again this would happen over time, not immediately. The final thing that comes to mind is that you have air in the RABS unit or a stuck dump valve that is letting brake fluid into the reservoir inappropriately. I have an intermittent low pedal on my 91 because of this. I have no idea about those power bleed machines but I have manually bled my 91 so it is not necessary to power bleed. It was a PITA when I had to replace the broke front to rear brake line and the master cylinder, there was air in everything, but eventually I got it all out.

What you said made a lot of sense actually.
I had to replace a small section of rear brake that got knicked with a grinder and I had lost a bit of fluid out of there. After that my ABS light was on and I only have rear ABS (they went 4 wheel ABS in 93).

The seals having water in them I'm not so sure about since I would think that the oil-based brake fluid would displace water in the seals but I guess it could happen. Now pushing gunk through, you might have something there. When we bled at the nipple my brake fluid was definitely not as clear as the stuff I was putting in. I guess a little bit of inside line corrosion over time could probably result in a lot of crap inside that brake system that we were trying to shove through the seals.

 

[FIND]

What you said made a lot of sense actually.
I had to replace a small section of rear brake that got knicked with a grinder and I had lost a bit of fluid out of there. After that my ABS light was on and I only have rear ABS (they went 4 wheel ABS in 93).

The seals having water in them I'm not so sure about since I would think that the oil-based brake fluid would displace water in the seals but I guess it could happen. Now pushing gunk through, you might have something there. When we bled at the nipple my brake fluid was definitely not as clear as the stuff I was putting in. I guess a little bit of inside line corrosion over time could probably result in a lot of crap inside that brake system that we were trying to shove through the seals.

Brake fluid can hold a LOT of water. Set a small jar of brake fluid in a cool place where it is out of the sun and open. After a couple months, look how much the volume and color has changed. Oil can hold water in suspension. Happens with diesel fuel, happens with hydraulic fluid, heck, it even happens with Gasoline, however, most brake fluids are not petroleum based, they are glycol-ester based, except for like DOT-5 stuff, which is silicone based.

Also, FWIW, I machine bleed brakes all the time, and I have a large vacuum pump that I bleed my brakes with at home even. You are probably just the victim of coincidence....

 

[guilleliz]

Hello guys, this is my first posting, I like your coments and agree with you, the brake fluid holds a lot of water, and very often the wheel brake cylinders get corroded inside and will acumulate a ring of hard calsium like material inside and the cup seals will damage when new brake shoes are installed causing imediate leakage on same cases,
I may need your help, I own a 92 XLT 4WD and the rear ABS light is on, it started itermitently and now is continuosly on, for what you said the 92 will have ABS on the rear only, I plan to replace the front brake calipers because this truck has tendency to wear the front brake pads and rotor on one side, this is the main problem i have with this truck besides replacing the radiator and w/p fan a couple of times, and O.H the trans. other wise I am surpriced how good this truch runs with over 200,000 mlls. on

 

[FIND]

Hello guys, this is my first posting, I like your coments and agree with you, the brake fluid holds a lot of water, and very often the wheel brake cylinders get corroded inside and will acumulate a ring of hard calsium like material inside and the cup seals will damage when new brake shoes are installed causing imediate leakage on same cases,
I may need your help, I own a 92 XLT 4WD and the rear ABS light is on, it started itermitently and now is continuosly on, for what you said the 92 will have ABS on the rear only, I plan to replace the front brake calipers because this truck has tendency to wear the front brake pads and rotor on one side, this is the main problem i have with this truck besides replacing the radiator and w/p fan a couple of times, and O.H the trans. other wise I am surpriced how good this truch runs with over 200,000 mlls. on

You can start your own thread when you have a semi-unrelated question.

Yes, a 92 has only rear ABS.

Start by checking all your brake lights. The ABS system uses the brake lights in an odd way....

 

[Tony H]

You may be pressing too far down on the Brake pedal when bleeding.
An old Master has a build up of rust on the cylinder beyond it's normal Travel. If you are bleeding the brakes and pushing the peddle to the floor, you are running the 'O' rings over this rusted area. Not good.

Fill reservior, put small amount of brake fluid in a bottle. Run hose from Bleeder to bottle. Make sure end of hose is in the Brake fluid... Loosen Bleeder, pump brakes slowly about 7 times, get out and close bleeder. Fill reservoir, Move onto the next wheel. The fluid in the bottle acts like a Check Valve... it makes Bleeding a one man operation.

You may have a low pedal if you didn't adjust the Rear Brakes up high enough.

Next time you do work like this, Push the brake pedal in and wedge a piece of wood up against the seat and the Pedal, with the pedal Pushed in, the Master will not drain.

 

[Baddecision93]

Brake fluid can hold a LOT of water. Set a small jar of brake fluid in a cool place where it is out of the sun and open. After a couple months, look how much the volume and color has changed. Oil can hold water in suspension. Happens with diesel fuel, happens with hydraulic fluid, heck, it even happens with Gasoline, however, most brake fluids are not petroleum based, they are glycol-ester based, except for like DOT-5 stuff, which is silicone based.

Also, FWIW, I machine bleed brakes all the time, and I have a large vacuum pump that I bleed my brakes with at home even. You are probably just the victim of coincidence....

Again, makes good sense that brake fluid could hold water in suspension.
Also makes me feel good to think that I may just be a victim of circumstance here. I guess since it's done there's no sense worrying and I should just be happy to know I now have a brand new part that should last a while.

You may be pressing too far down on the Brake pedal when bleeding.
An old Master has a build up of rust on the cylinder beyond it's normal Travel. If you are bleeding the brakes and pushing the peddle to the floor, you are running the 'O' rings over this rusted area. Not good.

Fill reservior, put small amount of brake fluid in a bottle. Run hose from Bleeder to bottle. Make sure end of hose is in the Brake fluid... Loosen Bleeder, pump brakes slowly about 7 times, get out and close bleeder. Fill reservoir, Move onto the next wheel. The fluid in the bottle acts like a Check Valve... it makes Bleeding a one man operation.

You may have a low pedal if you didn't adjust the Rear Brakes up high enough.

Next time you do work like this, Push the brake pedal in and wedge a piece of wood up against the seat and the Pedal, with the pedal Pushed in, the Master will not drain.

The one man bleeding thing sounds really intriguing. I think I'm going to try that next time. I do think the rears weren't adjusted enough. I think Ford just did it as quick as they could and called it good. I bought everything to redo the rear brakes so I'll just try to do a better job to get some good pedal pressure out of them when I change them.

Now what is it you're saying about how to not drain the master? If I disconnect a brake line and press the pedal down like that won't it just push all the fluid out?

 

[Tony H]

Again, makes good sense that brake fluid could hold water in suspension.
Also makes me feel good to think that I may just be a victim of circumstance here. I guess since it's done there's no sense worrying and I should just be happy to know I now have a brand new part that should last a while.



The one man bleeding thing sounds really intriguing. I think I'm going to try that next time. I do think the rears weren't adjusted enough. I think Ford just did it as quick as they could and called it good. I bought everything to redo the rear brakes so I'll just try to do a better job to get some good pedal pressure out of them when I change them.

Now what is it you're saying about how to not drain the master? If I disconnect a brake line and press the pedal down like that won't it just push all the fluid out?

Before you even Start to remove anything.

Pull the Fuse for the Brakelights so you wont have them on the whole time. Grab a 2x4 or something to hold the Brake pedal down a bit. This will close off the valves in the Master so fluid wont drain out.

It is when the Brake pedal is in the up position that fluid can run past the valves and down the Steel lines.

 

[Baddecision93]

That's really good information to know. I always wondered what I was supposed to do when I wanted to unhook the brakelines for any extended period. When I unhook my axle this is going to be good info to know.

 

[G-96XLT]

Sounds to me you're just getting hosed at the dealer. My master went on both the explorers over the years and I paid $20 for a used one and put it on in no time with a conventional bleed. I bleed all 4 with the truck off and then all 4 while running, worked fine for me.

For your information, going heavy on the brakes is what kills the cylinder. I took both explorers trashing in the winter on snow and was very hard on the brakes, by spring time they both had soft brakes.