Hello cougar enthusiasts. I’m new to the Forum, and I could use your help. Ours is a J code XR7-G. The car has sat for a long time, the truth might get me shot! My mechanic, who is a good reputable guy has overhauled the suspension and done a complete brake job, with exception of the calipers. This includes MC and booster. It uses the Midland type booster (yes Don, I’ve seen all your videos!) The one that’s coming out now I replaced myself and it has a band wrapping around it. They wanted $750 for the one with the band. My mechanic asked what was the difference, and they said $500. I tried a Scott Drake booster, before that. My guy said the new pads and rotors were a tight fit, but nothing was forced. We’ve got good fluid to all the lines but for some reason my pedal seems too stiff, and I can’t lock the wheels up on gravel. He’s got a few other things to try, but we didn’t expect to have this much trouble. Any help would be greatly appreciated. Thanks Ray.
Is there sufficient vacuum at the check valve on the booster?
Everything I can learn will help I will let my guy know thanks for the Post
I’m just guessing, here.
How is the proportioning valve? Is the brake light on the dash illuminated?
Is the pushrod for the master cylinder set to the correct length?
Has it ever had good brakes?
He should have rebuilt the calipers. The rubber o-ring that seals them gets hard as a rock. I typically have to use a grease gun to build enough pressure to push the pistons out.
If/when you solve this, please post the fix.
Not sure if it is the booster, but there is a procedure outlined in shop manual to check its operation. From memory, you run the car long enough to build up vacuum. Turn off engine. You should get 2-3 pushes on brake pedal before it gets hard. Then, hold your foot on the pedal and start engine. Pedal should fall away a little as vacuum is restored.
Here is another test procedure using a hand vacuum pump: http://ssbrakes.com/attachment/84298-Vacuum%20Brake%20Booster%20Testing%20and%20Diagnosis.pdf
Finally, make sure the hose supplying vacuum to the booster is vacuum hose and not fuel hose or something else. Non-vacuum hoses may collapse and choke off the vacuum from engine.
Thanks to everyone for the excellent suggestions I’m thinking of putting new calipers on the car, and yes the brakes were real good at one time. I will never let my cat sit this long again. When we get to the bottom of this I will post and let everyone know thanks again.
FYI, the usual OEM brake pads are dismal performers. Either the ebc redstuff pads or the Porterfield R-4S pads are much better at stopping w/o being hard on the rotors at all. My favorites are the ebc redstuff pads.
I know the pad selaection is not issue here, just throwing it out there that better pads make a HUGE difference in braking performance.
Z
Thanks Z. Throw anything out there I’ll catch it all
I’m going back to basics here. Bill said we should have rebuilt the calipers, I’m going to get new ones. Correct me if I’m wrong, I should have 18 inches of vacuum at the booster. If it comes up less than that, where would the vacuum loss be coming from? The calipers are about the only thing we haven’t changed, as far as the brakes go. Same port, same line to the booster. SOS! I’m dying to drive my Cougar again. This car used to stop better than any car I’ve owned.
Re:
I forgot to mention we put the new proportioning valve in, and brake still aren’t right. I have to think I’m losing vacuum somewhere. Thanks for any and all help.
Ray.
Just throwing it out, but did your mechanic rebuild the old master cylinder, or replace it? If replaced, was bore size checked to insure it was the same as the unit being replaced? Although a parts store replacement should be the same, it can’t be taken for granted that a “look alike” replacement but with different internal specs wasn’t substituted. I’ve learned from experience that installing a MC with an oversize bore will result in a hard pedal with minimal travel. Something else to check, if all else fails.
Why so much for the booster? $200-$250 is the standard rate for a Midland rebuild these days. Unless of course you add a core charge into the mix.
https://secure.cougarpartscatalog.com/brkboost.html?attribs=76
I’ll ask my mechanic about the master cylinder yes we did replace it the other one was leaking fluid into the booster. Don, both boosters I spoke of were the Midland type but I think the old one that I put on many many years ago had a strap wrapping around it will a tensioner on it and I think the new ones are just spot-welded. The auto parts store wanted 750 bucks for the one with the tensioner on it, and said the only difference was $500. I wasn’t going to spend that much so the one I got cost about $250. Thanks for all the help, I’ll let you know how I come out.
Ray.
Okay. The G is back on the road. Man did it feel good to drive it again. Turned out, the brake issue was the proportioning valve. I would have one of the early ones. I guess the newer ones have springs in them to reset. Mine, you have to use the bleeders to get the light to go out. I still need to replace or rebuild the front calipers. I should be able to lock the brakes up and skid on a panic stop. I guess it’s a Lincoln till I get those changed out. (Town Car). They respond but not as well as they should. I also had a broken wire in my alternator loom. My mechanics brother spliced another wire in and now the low fuel light stays on all the time, even if I pull the key. I thought I saw the whole loom at WCCC. I think that would be the way to go, as electrical isn’t my strong suit, at least not splicing. Don you may get an SOS if I can’t locate the loom on your website.Thanks to everyone for all your help. I’m sure you’ll all hear me whining in the future!
Ray.
The red wire with a ring connector at the end of the headlight harness at the starter solenoid area is for the low fuel prove-out circuit. It is supposed to go on the starter motor side, not the battery side, which (based upon your comments) is where I suspect it is located.
If WCCC can’t provide a headlight harness, I probably have on that can be refurbished for a modest price.
Thanks so much for the tip Midlife . I will check that out when I get home from work tonight . Man, I do love this forum!
Ray
Dr Midlife,
Your diagnosis was spot-on, swapped the wire, problem solved. I’ve owned this G-car, since 1983, and I don’t know where I would have been without the internet and this forum for tech support. I still have a long way to go, but it sure feels good to drive the car, and I’m looking forward two posting pics, and letting the cougar community watch this thing come together. I’ll tell my whole story later, for now I’ll just say thanks again for the help. It would be great to participate more and meet some of the cougar guys across this great country of ours.
Glad I could help!
Well then!
This certainly is a viable option for me. But I’ve never dug too deep into harnesses, and I’m definitely no electrician. I would be interested in getting a reproduction harness from WCCC, and having you convert it so it would run my factory tach. I would also have you know I have a short in my interior lights. They worked for about 1 minute and haven’t come on since. I have no lights inside the car save for the dash. The car spent most of its early life in California baking in the hot sun and a lot of the wires are brittle . l’ll contact you when I am ready to proceed. Can’t seem to thank you enough, so I’ll do it one more time. Thanks.
Ray.