Hey there fellow Cougar lovers. Yesterday was a most productive day working on both my Marauder and Cougar. I wanted to get some things done that haven’t been done in a while. I recently just passed my purchase-versary with my Cat. It’s been a quick 7 years. When I first got her I did a lot of the usual things one would do to a recently purchased classic car. Doing the brakes in 2011 was one of them. Back then I did disc pads up front and drum shoes in back, new spring kits and rotors as well. I also bled the brakes then as well.
In 2011 I ran into the issue of not being able to bleed the rears and with some assistance fro the group here, a recommendation was made to replace the rubber brake hose that goes over the rear axle as it can dry out on the inside causing it to close off on itself when bleeding. I replaced the rubber hose with a SS brake line, as I also swapped out the front brake hoses to SS lines as well. This seemed to take care of the issue as I was then able to bleed the rears.
Fast forward to yesterday…started by trying to gravity bleed the rears at first, just opened the bleeder with a hose on it to drain into a pan and nothing came out. Tried to push the brake pedal as well with the same result. Nothing coming out, from both sidesa. Could the SS brake line that goes over the rear axle close to the exhaust be the culprit again? Or would the group be of the mindset that the brake distribution or proportioning valve on the inside fender perhaps need to be looked at?
Right now she only has front brakes with is not ideal but evidently I have been driving her for that way for who knows how long now.
I would narrow down where blockage is located. But it is messy
start at furthest point from master cly and start opening/loosing steel lines while someone applies pressure to brake pedal.
when loosened if no fluid flow, tighten and move up the line closer to master cly. once you have flow start looking at components with in blocked area.
Thanks Bill. Wasn’t sure what was inside the SS line. I am thinking that might be a good place to start. It was great digging into this much needed upkeep on both Merc’s.
Often the steel line from the front of the car to the rear gets clogged with rust. It’s telling you that it is time to replace all the hard lines when that happens.
I somehow had an extra front to rear brake line left over from the restoration of my '70. Still in the original box. For a front disc/rear drum car. Not sure if they changed anything that would affect brake line fitment between '69 and '70, but If you can use it, I’ll make you a deal.
Here’s a tip for ya, not sure if it’s too late at this point. But when you start messing around with brake fluid pressure and bleeding, it’s easy to throw off the alignment of the shuttle in your distribution block, which triggers your BRAKES warning light. And getting that re-aligned isn’t fun. So there’s this tool that holds that shuttle in place while you’re bleeding and stuff. It doesn’t need to be much more than finger tight, but it keeps that thing centered until you’re all done. Here’s a pic I made to show what I’m talking about:
Yep - on 69 up this can be an issue. IIRC the shop manual has a description of how to recenter without the tool but in any case the valve has to be centered to prevent it from blocking the rears for safety.
The position of the switch doesn’t affect the flow of fluid to the rear or front. It’s just turning the light on. It has no effect on safety. It cannot “block the rears” as you suppose.
No judging…So a follow up here on this project of mine that got started a loooong time ago. Just last weekend I finally installed the new stainless steel tube that jumps the rear axle. After getting it installed and having a buddy pump the brake pedal and hold so I could open the bleeder valve I was still not able to get the rears to bleed. Very frustrating needless to say. Another buddy of mine asks, are these power brakes which I replied, yes. He said, try starting the car. So I did. With the car running I was able to bleed the brakes beautifully in the rears. No issue at all.
So I am scratching my head thinking, is this normal way to do them? I do not remember dong them this way last time but I will do it this way the next time when it is time.
I’ve got to agree with Royce. It really doesn’t seem like the brake pressure switch spool should be able to block the fluid pressure from the master cylinder. The front and rear are separate systems why disable the rear even if the pressure is lower. I just rebuilt mine and the spool dimensions are just like the attached drawing and it would not block flow even with the switch activated. You will definitively need to recenter the spool and get your warning light out, and the warning switch functional should you have a failure. Anyway, with blockage in the rear system the spool would likely have shifted to the front brake side while bleeding. You need to work backwards from the rear brakes and determine where your blockage is as has been suggested above.
There are cautions about running the engine when bleeding the brakes regarding the potential to damage the brake booster. I know this is the case with the Bendix booster.
Royce, actually it does stop fluid flow in 69-on…this was a safety feature added. You have to keep the valve centered otherwise the rears or fronts get cut off from flow. The tool works but there is a shop procedure for getting it to recenter. Surprised you didn’t know that one.
Actually… If you bleed the brakes with the car running there is a VERY high risk that you will damage the bakelite hub as the pedal will over extend and crack it. We get a booster a week turned in at WCCC because of this installation error. This warning is called out with the purchase of every rebuilt or NOS FORD booster. Not sue why your brakes refused to bleed without the help of vacuum assist.
I did have one '68 Cougar (not mine) where we could not get the rear brakes to bleed. I started disconnecting lines to see where the blockage was. Turned out the long line from the front of the car to the rear was rusted solid and would not pass fluid. We replaced all the brake lines on the car which fixed the problems.
