I’ve read all the post here and decided to post my problems. 1989 ford f250 - 351 Great truck but since I’ve had it - it has had the soft pedal when braking. It would stop you but pedal would be way down when doing so. I decided to replace booster master cylinder and the calipers on front along with the two front soft brake lines. Primed master and with all installed I’m trying to bleed starting at right rear. Rear brakes i have fluid coming out. Not squirting out like normal when brake pedal is pushed but it does come out. Front calipers - right caliper has tiny amount out but can’t get any fluid to amount to anything out of front calipers ? I did bleed rabs and have great pressure there when cracking open. I just can not understand why no fluid coming out of front lines ? Master cylinder is new not rebuilt and when you remove the two lines from it and press pedal you get fluid out with good pressure. I’m stumped and any suggestions is appreciated.

 

It sounds like you have not adjusted the rear brake shoes. Yes they should self adjust but things can happen that they do not self adjust. I would start by doing that. It can be a bit tricky to properly get them adjusted even if you are used to doing it. The best way is to tighten them until they have a heavy drag and then back them off until there is no actual drag but you will still hear some clicking as you turn the wheel by hand. This is complicated by the drag of the rear drive train. Also when you go to back the tension off from having a heavy drag, you usually have to push back on the self adjusting tang through the adjusting hole as you back the adjuster off. As an alternative you can just tighten the rear brakes up some. Just my way to do it. And of course my assumption the rear brakes need adjusted.

 

The complete bleeding process in in post number 6 of this thread https://www.fullsizebronco.com/threa...eeding.382217/

The easiest way to adjust rear drums, assuming the brake shoes and hardware are in good condition, it to work through the backing plate, with the wheels chocked and the truck in gear (manual transmission) or in park (automatic transmission), and the parking brake released.
Rotate the adjustment star wheels up, to tighten the brake shoes, until the star wheels are reasonably tight.

From under the truck, rotate the star wheels up, to tighten the brake shoes, rotate the star wheels down, to loosen the brake shoes.

Rotate the star wheels down about 3/4 of a turn.
Take the truck on a 20 minute ride. Feel the backing plate of each rear drum. It should be warm but not smoking hot.
Chock the wheels and put the truck in gear or park before working under it.

 

Actually adjusting rear brakes was done months ago before i ever started replacing parts. Rear were actually in good shape as far as adjustment. My concern is why no brake fluid coming to front calipers ! Even though it’s a “new” master cylinder i think it may be bad even though i get fluid out of ports when lines are disconnected. My buddy held fingers over front and rear ports on master to prevent air from entering when releasing pedal and said he sealed them pretty good - got good flow when pressing pedal but yet i still have no fluid coming out when i try to bleed front calipers ? I’m baffled

 

Were the brakes good or spongy when you got the truck. Have the brakes gotten worse as you have put miles on the truck?

That is what it seems like to me. Parts unnecessary replaced.

 

My4 you’re right about parts but i paid 100.00 dollars for the truck ! Wasn’t running when i pulled it home with a tractor from my neighbors yard. I replaced starter solenoid and put a battery in it and it fired right up. It’s a 4 speed with 5th wheel in bed and absolutely no rust anywhere and makes an excellent wood truck. I put a new clutch in it and fixed floppy steering wheel and spark plugs and now working on brakes. I think i can afford to spend a little money on it. The brakes have always been soft and had a lot of travel. They would stop you but pedal is almost to fire wall ! But now i have no brakes and I’ve read many times that this is common for the ford trucks in this era to have soft pedal. I can live with the soft pedal but the brakes have to stop the truck ! I don’t consider it a waste even though the parts i replaced were probably ok. The lines coming off of calipers definitely needed replacing - didn’t leak but were pretty rusted. I am going to put the old master cylinder back on just to rule out a bad new one. Will post more on findings or if i find problem

 

Spending money on parts that need to be replaced is different then arbitrarily replacing parts that are still good.Assuming the master cylinder is good and the rear brakes are properly adjusted then I would check the RABS valve on the frame rail. What you have read about being common or normal is wrong….the truck should not have a soft pedal.

 

Does the rabs only effect the rear ? I will remove and check spring or possibly remove spring - wanted to read more about that ! Not above replacing rabs if it’s in bad shape but as far as not getting any fluid out of front lines will need to be solved before i get into rabs.

 

Yes. Rear Antilock Brake System.

I’m not convinced you only have a front brake problem.

Does “primed master cylinder” mean it was bench bled? You are not getting much fluid out of the rear except for the RABS valve. To me it seems like you have a lot of air in the system. Did you try gravity bleeding or went straight to pressure bleeding? Try opening the RR wheel cylinder or even all of the bleeders at the wheels and let it go while keeping an eye on the reservoir level.

 

I did bench bleed before installing and master even came with fluid in it half full. I’m sure it has air but I’m going to try the gravity like you mentioned and keep eye on reservoir and keep full. Never bled that way but i don’t have a system to backfill. I appreciate the input !

 

I may buy a system to backfill - any suggestions on a system ? Don’t really want to spend 500.00 but would like to know which one works best for the $

 

That’s a red flag for me. I have never seen a brake master cylinder that already had fluid in it. Clutch master cylinder, yes, but never a brake master. I don’t understand what you mean by “I don’t have a system to backfill.” You aren’t able to keep topping off the reservoir?

Instead of bothering the Mrs. to push the pedal, I bought a Motive Products pressure bleeder several years ago.

 

Lol that’s exactly what i did ! She complained about her leg being tired but i told her - just a few more times. Will check on the motive product. Thanks

 

My4 yes i can top reservoir off if it goes down but it never emptied into front line ! Front piston of master wasn’t pumping fluid ! Anyhow - Wanted to post an update - so after putting suction on front calipers to remove air - getting no air only brake fluid i still had no brakes on front. Back brakes worked great so i decided i would replace the new (not rebuilt) master cylinder that i bought from Oreilly’s. Only solution i could pull out of my problem ! So i purchased another new master cylinder from - yep - Amazon - it came in two days and was half price of Oreilly’s. I removed new master cylinder put new one on and have the best brakes the truck has ever had !!! No travel on pedal and brakes are working great. I can’t remember ever getting a bad new part before and this has caused a lot of headache for me and a couple buddies and my brother who’s been a mechanic all his working life ! He said not likely a bad master but it was. Dorman is the brand from Amazon and I’m just glad brakes are fixed. This - I’m sure Chinese part from Oreilly’s - has caused a lot of headaches. Plan to return for refund and let them know they should look into another supplier ! I appreciate everyone’s input on this and lesson learned just because it’s a new part means nothing to me anymore !

 

My 1996 F250 351w has always had a soft pedal, now my entire system is replaced even the booster, literally everything but the RABS unit is new, well the booster is a reman, but I dont have the no fluid at the caliper problem but I do have a spongy pedal and a new Brakebest master cylinder from O'Reilly Auto & now I am pretty convinced it is the problem