RV Repair Questions? Ask an RV Mechanic for Answers ASAP
Sorry for your trouble, why did you change the master cyl & power unit. Was there something wrong with your brakes? Have you corrected the other problems? Thanks for coming to Just Answers. Jim!!!
The master cylinder was leaking bad, I have been talking to
Ron, but wasnt happy with the answer
I ordered a new Master cylinder from Alretta Truck and Coach parts in Massachutus, he would not sell it to me untill he talked to me on phone as copper top hat washers seal are not available and we wanted to make sure I knew. as John Deare only made the right amount as what was on the production line.
we have checked the casting Numbers to check its the right one.
We fitted the new master cylinder, blead the brakes with and oil can and then 3 pumps on each wheel like we always do.
we change the brake fluid every year.
So we set off for a week end away and we got about a mile from home and we
had a pedal with 1" play for Bendix power Brake unit,and about an 1" before brakes went solid.
the pedal seamed to be self bleading till there was no play and brakes were binding.
the only way to release the brakes was to release some fluid and then we could travel for a bit then release some more and we got home
so what I have done is in the first question
This is a Fleetwood Southwind on a John Deare Chassis with Ford Running Gear
and we have owned it for 6 years
enclose photo of Bendix power brake unit which master cylinder to
see what type of brake unit I am talking about
as most people dont know this vehicle
The other chap Rod just said faulty Mastercylinder not good enough for the people wher i brought the master cylinder
I had the same problem with the unit, I'm not sure weather you have an oil or vacuum assist unit. as far as the copper washers, are you talking for banjo bolts. Youu can buy an assortment at any auto parts store. sometime you will need to readjust the push bolt between the power unit and the master cylinder. If the adjustment is off it will not allow the fluid to return to the resivoier, kind of like pumping up the brakes and keeping the pedal partialy applied. if you want to test to see if this is the problem you can remove attaching nuts and put 2 or 3 flat washers in between power unit and master cylinder put the nuts back on and try it.
get back to me and let me know if this works, if so you are going to have to adjust the push rod. Jim!!!
You cant put washers between bendix unit and master cylinder as it will push seal out on Bendix unit and you have TQF oil all over the floor.
The copper washer have a tube attached to them ,they were turned on a laithe
The system has a pump the same as power stearing which works the power brake unit
The end of the Master Cylinder is re-sessed and the Bendix power brake unit fits into the end to stop it moving,
With the master cylinder off and very lightly press the brake pedal you can watch the piston come out and return home fully no adjustment on it ,Thats the 1 of the photos I sent you
I have tried with master loose because some one else told me to try this and had to put new seal into Bendix power unit
The Biggest problem is no one understands this kind of power brake unit designed by John Deare
The new cylinder is Identical to the old all measured and checcked with a Vernier to the thousandth of an inch
I am an mechanic and an engineer but this has got me stumped,I can usually mend anything
This system is Hydraulic TQF or ATF power brakes with dot 3 brake fluid in master cylinder
Any time before when we have had brake fade when fluid get hot or brakes not wanting to stop as well as usual we just drain brake fluid and replace blead brakes and problem solved.
this has got all new brake fluid in completely drained and refilled
push rod not adjustable
there's play on pedal linkage when brakes are on and binding,so its not adjustment at the other end
the rod from the pedal in the cab only adjusts the power unit have tried messing about with adjustment on side of road to get me home
sound like possibly the master cylinder has been fitted with check valves, possibly for rear drum brakes. to release brakes do you need to open both lines or just one?
one front wheel only to release
disc's all round same calipers on front as back disc pads are universal
Realy sounds like the master cyl is is not releasing the fluid back to the resivior the second piston may be stuck forward or just not returning to the neutral position. Where did you purchase the master cyl? They realey shouldn't give you any trouble replacing the master cyl itt is a safety issue. If I can be of any help talking to where you purchase it I would be glad to help.
sorry i was at the car auction all day today.
The Master cylinder was purchased from Geoffery Rosenburg, Alretta Truck Parts INC,BLD#5B, One , Watson Place,Framingham, MA. 01701 Tel (XXX) XXX-XXXX.
My Name is William Blain,delivery address was 12,Coningsby road, Sc**thorpe,North Lincs, UK
My Tel 0XXX-XXX-XXXX
order No 51766
If you could explain your finding to Geoffery I would be very grateful
I will give them a ring today and see what i can do. Jim!!!
thanks, XXXXX XXXXX to American shows allready
Motorhome has graphix pictures all over it and they always put us in the middle of the show ground so missing the time out at moment.
And Americana biggest show of the years is comming soon
Did you manage to talk to Geoffery
Good afternoon. I just got off the phone with him. he is going to talk to the techs at the company that manufactured the unit and call you or email you about it. His sugestion is to look in the resivoier and make sure the ports are drilled in the proper place to allow the fluid to return to the resivoier. I'm not sure what he is willing to do about your master cyl. He seems to think you have a proporting valve on the side of it that may be yuour problem. I said you didn't have a problem just a leaking master cyl. lets see what he comes up with for you keep me in the loop.
he still thinks you may be doing somthing wrong, but give him a chance.
the two little spring loaded valves between master cylinder and reservoir were stuck
problem seems to have solved its self
will let you know when i road test