1985 Brake Problems
 

I have an 85 F250 XLT lariat which currently has a brake leak somewhere on the front drivers side. (It leaks all over the left front frame rail.) It looks dry around the master cylinder, (was replaced by mechanic, don't know if they did it right?).
Anyway the wettest part I can find is where the lines split from that metal connector. I thought the brake lines going to the back of the truck looked loose so I tightened it and it seemed to make the brakes work again but the reservoir level dropped and it seems to be leaking again. If anyone has had the same problem as me I would appreciate any advice I can get.

First off, welcome to the forum.
Now then, I would check all of the fittings, from one end to the other. I would unscrew them, clean them, check them for any stripping, repair any issues, and then re-tighten them properly. Then, I would check for the issue once again. If the problem still exists I would start looking for a possible split in a line. You might also check for any leaking coming from the underside of the booster, master cylinder, or equalizer valve. I guess that would be a good start. Once you have found it and fixed it I would completely bleed all of the brake lines until fresh clean fluid runs out all of the bleeder screws. Good luck and let us know how it turns out.:-wink

I don't have that problem. But, I have developed a method of finding leaks on things prone to having fluid run down and get on everything: Clean things completely with brake cleaner and then wrap the suspected part with blue paper shop towels and secure with tape. Check frequently during/after use. I usually can find the leak pretty quickly that way as the towel will get wet where the leak is and, if checked frequently enough, that's the only place that's wet.

That is a really good idea, I may have to try it sometime.:-X22

The problem appears to be where the brake lines split front to back. The reservoir for the back brakes drops really quickly but the one for the front doesn't at all. I'm going to try and replace the connection I guess? I'll probably try the blue towel thing, then hunt more parts cry a bit and hopefully it works. If it doesn't I'll probably set it on fire. I'll update again in a few hours.

Good luck! Stay away from the fire idea. Lots of us would love to have the parts. ;)

The problem is that pressure/regulator valve thing. Probably, anyway I've got the towel in it and I have to hunt one down for my mechanic. Any suggestions on where to get one? I'm not going to a junkyard fyi. I'll probably try Lordco. My mechanic says it's something like 1-200 bucks to do my pressure valve thing and another 5-600 for tie rods the drag link and an alignment. What does everybody think about those prices.

I think paying 100 to 200 for the proportioning valve when you could get one from a salvage for ~$5 is way steep. What do you have against salvages?

The 1-200 comes from the labour involved in redoing all the lines surrounding the valve. There are no trucks of this generation in junkyards around here. I called 6 junkyards and there's only one truck with different brakes than mine with huge rust. I prefer new parts anyway, well that's not true, I prefer not having to fix **** but, oh well. The price seems reasonable to me, all labour for taking rusty, ****ty things apart. Nothing has been easy on this truck.

Works for me if it works for you. Didn't realize you don't have any of these trucks in the salvage up there. Good luck.

Okay, the valve on the frame is the Proportioning valve and mine is not working well and is leaking also. There are plenty of spare(i.e., used) parts in this neck of the woods, but like you, I don't trust used parts when it comes to the brakes(bad brakes could kill someone). The valve is easy to replace. There are only five lines to loosen and two bolts that hold it to the bracket. The problem comes in when bleeding. The bottom of the valve also needs to be bled(the spring portion at the bottom of the valve doesn't bleed well). It takes a 3/4 box end wrench to loosen.
You MUST have clear new fluid flowing solid(no bubbles) flowing from it in order to ensure that the valve has bled properly. Then, bled the brakes normally.

A footnote: if the new master cylinder has not been bench bled properly it will not work(spongy pedal, soft brakes) properly.

Yeah I'm pretty sure the master was done right because when i top up my brake fluid I can lock up all four wheels. Very quickly after that it doesn't work anymore. To be quite honest I think one of the lines might be split as well and I don't really have the time/ knowledge/ tools to be screwing around with my daily drivers brakes. I feel way more comfortable painting something than pulling on my rusty brake lines. The truck is rusty . . .

I hate rusty stuff--makes things way more difficult....:-X15

Make sure it is not a line that has rusted through....

Like my rear fuel tank, and I missed the part about the line in your reply

The problem was the proportioning valve part of the brake metering valve/proportioning valve assembly. There are no assemblies around here only one truck I found within 100 miles. Also Ford doesn't have the part either.Anyway the universal proportioning valve was 70 bucks and my mechanic charged me 100 bucks to plug up the broken assembly and route the line through the new proportioning valve. The light on my dash which tells you when you lose brake line pressure doesn't work anymore as a result of the ghetto fix. It never worked but anyway this is how my problem was resolved. Also I tried the blue towel thing, I went to the grocery store and back home and the towel was absolutely soaked, like less than 5% of it was dry lol.