Have any of you guys heard of any problems with honing out wheel cylinders too far other than leaking.

Here is my story, when I purchased the truck it had no brakes, after my upgrade with modern drivetrain I used the 1986 F-250 power brake booster and master cylinder and ran all new lines.

The original wheel cylinders are UN-obtainable except thru a select group of guys that swiped up all of the left over Napa stock, they now want 90 dollars a piece for them which is the same amount Apple hydraulics and some of the others want to rebuild them with S.S. I have 6 of them in the truck and this amounts to alot of money for me.

I removed the originals and honed them out, they were rusty and pitted, when I say honed I mean bore maybe. I sat there with a bucket of water ( or oil, cant remember what I used ) and went thru 3-4 of the small drill driven honing tools you would find at Napa. I sat there for hours, I never did get rid of all of the pitting but they looked alot better.

I was able to purchase new kits to put them back together and did this.

I bled the brakes and never had a leak but also never had much of a pedal, if I pumped it once or twice than all was well but on first stomp of the pedal it usually went nearly to the floor.

I adjusted the brakes time and again according to the procedure given in the service manual.

The original 52 F-7 Ford braking system used a large booster mounted up under the floorboards.

All I did was mount the 86 booster/master cylinder on the firewall and run new lines down to each wheel, no proportioning valve anywhere just straight lines to the cylinder, one T in the front and one T in the rear.

I am fixin to get to the point of doing the brakes again and would prefer again to not spend the 90 dollars to get these correct wheel cylinders but want this to be done with.

I have heard that the F-7s are notorious for being hard to bleed, I bled them and bled them and bled them a few more times, I tried this over and over again.

I have never been able to figure out whey I did not have a pedal. Any input would be appreciated.

 

7EQ-2061 .. Front Wheel Cylinder 1 1/4" / Obsolete ~ 1 available NOS (TX)

2Q-2261-A .. Rear Wheel Cylinder 1 5/8" (w/o tandem axle) / Obsolete ~ 1 available NOS (TX)

Have you tried joblotauto.com, located in Queens NY that specializes in BIG Ford truck parts?

 

Seems to me if they were honed to far they would leak by the seals. I would think if you arent losing fluid there is another reason for a low pedal.

 

sounds like you may need some kind of residual pressure valve.

 

I asked the same question on another forum, these are the responses I received, I was already leaning to maybe the Master cylinder being a problem, anything you guys would like to elaborate or add to after reading this might help, Thanks

You need a proportioning valve.....Plus, that 86 MC is made for disk brakes on front.

As for the wheel cylinders, if they are not leaking and they push out the brake shoes, they are good.




That '86 MC just may not be moving enough fluid. With that said, remember that brake fluid is virtually non compressible and that all you are doing in effect is moving a solid that can go around corners to push something flexible out. I believe that what you have are two opposing wheel cylinders (Lockheed brakes) in the rear similar to what Chrysler used for many years - and were less then great. If you need 3 oz to move the wheel cyls out and are only moving 2 oz ..... You have said that the replacements are in the $90 range - and that others have cornered the market. If indeed these are opposing wheel cylinders, look at the various, at least through the '50 and possibly further if I recall, choose one that is close in size and give it a try - I use Rock Auto Parts for my search.



Did you bleed the master cylinder? This is a separate and messier function from bleeding the wheel cylinders. When there is air trapped inside the master's piston the braking will be minimal at best. Additionally, the 86 master is for disks up front which use very little fluid to actuate compared to drums.

all of the above plus you can power bleed the system if you think you and your bleed partner are missing some air. do it twice.Make sure fluid is coming out clean before you tighten bleeder.
You can also use your finger over bleeder opening to prevent air being drawn back in if you must bleed with out power bleeder and you are not sure about partner lifting the pedal too quickly.

 

Does some fluid "pop" out when you pedal and then crack each bleeder (in separate events)? If not, you do need (a) residual pressure valve(s).

 

+1 You can't use a disc/drum MC for drums without adding a residual pressure valve. Compare MC piston diameters, original vs. donor, too.

 

I agree with whats been said, if the honed out wheel cylinders aren't leaking then they aren't your problem. I would start looking at the donor MC, and, specifically as Ross has said, the bore of the MC.
The donot MC is for a disc/drum set-up, and won't be right for your all drum set-up. You should be able to find a decent donor MC from and all drum system.

Google can be your friend here, there are lots of good articles on the web explaining brake systems and what effects changing MC bore and/or wheel cylinder bores has on braking and pedal feel.

Good luck
Bobby

 

If you don't have a brake fluid leak then you still have air in the system. Check on google for how to make a pressure bleeder , very easy and cheap to make . In addition look to what others have said regarding correcting your MC choice and installing residual and proportioning valve .

 

I think that with an all drum brake system you don't need a residual valve....but don't quote me on that

 

Thanks, I do have a pressure bleeder or vacuum bleeder and use it. Can anyone tell me if fore instance in 86 did Ford build a truck with drums all the way around for brakes, I have little choice but to replace the master anyway and I will need one that will bolt onto the 86 booster with no mods.

Thanks again for all the tips/suggestions, it all helps

 

Not sure on this, did not check that specifically.

 

Yeah, you do, even if the MC is up high (not under the floor). Otherwise the pistons retract all the way and it takes a couple of pumps to get contact. I thought I had it written down somewhere but I can't find it; I think drums need a 10 psi RPV, discs only need 2 or 3 psi. A Search will find it on here, Ernie/Eman92082 had a thread on it: https://www.ford-trucks.com/forums/1...drum-drum.html

 

Ross,
That kind of rings a bell. I knew there was some kind of difference between the two. Its been awhile since I converted my truck to front discs and I've killed off those brain cells.

I'm pretty sure that all 86 trucks were disc/drum, you'd probably have to go back to the mid to late 60's to find an all drum set-up. I know my old 69 F-250 was disc/drum.

I don't know about larger trucks (1 ton and above)
Bobby

 

When you say residual valve are you referring to the proportioning valve? If so I though the proportioning valves job was too make sure that an equal amount of fluid went to each wheel cylinder, maybe that is incorrect.

I did not know that a proportioning valve helped maintain a certain amount of fluid from flowing out of the wheel cylinders ( or kept the master from retracting back all the way, not sure what piston you are referring too ) and then back into the M.C reservoir?