My 1970 Cougar (351c-2v) has long had the braking problem of
Brakes are bled and master cylinder is full.
Is this a power brake booster problem (if so, what) or something else?
Any thoughts?
DOB
I won’t say that you’ve definitively “hit the nail on the head” on your Cougar; if for no other reason than that there are a lot of guys on here that have dealt with more brake problems than me.
However, those were EXACTLY the same symptoms that proved out a failed vacuum brake booster (ruptured diaphragm) on my first car, a '73 Gran Torino; and would be my very first ‘educated guess’ as to your car.
x2 to what Dawg said
Thanks for the thoughts. I suspected as much. We’ll go that route.
DOB
ProTip: remove your booster and send it to be reman’ed, instead of putting yours in a core box and sending it back in the hopes you got the right one only to find the one they ordered for you is the wrong one.
I’ve had this happen to two different Mustangs I wrenched on, and it’s a pain in the scrotum.
It went something like:
Order booster
Bring in core.
dude boxes up core and takes it away.
I take booster home
Find out booster is wrong
Dude already sent his cores in, so the original is now gone forever.
I did that ←
Andy; been there, done that.
(In no particular order)
'76 Chebbie 1-ton P/U starter…Freakish factory design, 350 small-block and Turbo 400 trans. After failures with every auto supply house in town; Old Guy at the only independent store in town sold my a starter for a '69 3/4-ton with a 292 and wide-ration four speed. Last starter I ever bought for that truck; still cranked great when the engine grenaded.
'91 Chebbie Silverado with a 4.3 V6. (Great truck, only replaced two “hard parts”, not counting brakes, u-joints, etc) The water pump “changed” for 90-92 models; so did the A/C compressor. Guess which two “hard parts” I had to replace.
My wife’s '02 Dodge RAM1500… (the bstrd year). Parts counter guys spent much time telling me that I had the year wrong, or that I “needed to check with a professional” because '01 was the last year for the 5.9 MPFI (Dodge 360); so therefore I either had an '01 or older pickup or “Yeah it’s got a Hemi”. Wrong on both counts. Injectors, alternator, distributor cap/rotor, plug wires, serpentine belt, belt tensioner, A/C compressor.
The Dodge replaced her '94 Pontiac Grand AM -just in time, too, as I was casting about for some kind of compound that would be regulated by the BATFE that could put that car out of MY misery!
The list of “nope that was not the right part” can best be described as everything under the hood without yanking the engine/transaxle… which was pretty much everything I ever had to replace.
Before the Grand AM, she had an '86 Ford Tempo with the pushrod 2300 cc engine and automatic transaxle; and before that (when we first met) she was driving a '76 AMC Gremiln. Need I say more?
EDIT: Yes I should have said more… like an unaccountable number of wrong thermostats for my '73 Gran Torino; because all the chain-store parts guys didn’t know anything other than what the “computer” (RS-232C terminal) told them. And, “the computer” or their parts catalog (or both) was/were very certain that ALL 2V 351 engines were Windsors for 1973!
Needless to say, unless the core charge is extraordinary; I’ll pay the charge, make sure the part works (or if it even fits) like the store’s database says it will - then come back with the core and my receipt.
and here i thought all rs-232 setups could do is beep… hmm…
DD, same thing here with my own ‘bastard year’ '97 F-250HD. '97 was the intro year of the ‘new body style’ F-150 and ‘light duty’ F-250. Neither of those latter two came with pushrod engines or twin I-beam front suspensions. The F-250LD even had some odd-ball 7-lug wheels!- and of course brakes, rotors, etc.
The F-250HD and F-350 remained the ‘old’ body style until the new Super Duty came out in '99. Wanna bet how many times I’ve gotten wrong parts even though I specify ‘over 8800 pound GVW’? Try finding an exhaust for it, too, since our white elephant has a 460 engine, with a 3" in and 3" out catalyst. 3" in and dual 2" out muffler (and dual tailpipes)… Fan belts… Spark Plugs… Brake rotors/drums… even the front suspension parts! Heck, even the tire selection macro at most online tire stores doesn’t list our 235/85-16 load range E tires for '97… One parts store counter-guy insisted that my '97 had to have a 5.4 until I walked him out to the parking lot, opened the door, and showed him the door tag! I’ve threatened to just call it a '96!
Yeah, Milo, that F250LD designation was NOT one of Ford’s better ideas. They finally re-introduced it sometime after 2000 (I think) as an “F150-7700” -the latter numbers were to indicate the GVWR. But it STILL came with the 7-lug wheels!
More scarey (to me) is the “fleet service model” F250, which came out in the late 2000’s (I drive an '08 at work). It’s got the Stupid-Duty frame under the sheet metal, but I can tell you the front and rear disc brake calipers -and pads- carry the same part numbers as those on my '02 F150 4x4. The last time I put “my” F250 on a truck scale, it weighed right around 7800 pounds (old beam-type scale) with 1/2 tank of gas and me out of the truck, operating the scale. Needless to say, my foot is on the brake pedal a lot sooner than it is with the F150; unless the F150 is dragging a trailer with no brakes of its own.
Actually, the 7.5L automatic F-250HD ext cab shortbed weighs about 700 pounds less than my former tow vehicle - the 460-powered '77 Country Squire I bought in Apache Junction back in '91 when I was visiting the folks. Honest! The wagon weighed in at 5400 pounds empty and the truck ‘only’ 4700-ish when we were buying bulk landscape supplies. You know, weigh-in before going back in the yard, the weigh-out when you’re done loading. That one time we used the wagon, I had loaded 2700 pounds of landscape rock in there, and it still wasn’t on the snubbers (Moog cargo coils FTW!). Brakes? 4-wheel disc (yes, on a '77!) with the hydro-boost braking system. The truck? lets just say that I was ‘over gross’ - and that is a 9800-pound GVW! You do the math.
BTW, the F-250HD has four piston front calipers on the front and 12 x 3" drums in the back! The F-250HD got the F-350 frame, rear springs and rear axle, but the ‘regular’ F-250 front suspension. Yet another thing that makes it an oddball!
Don’t know the empty weight of “my” '08 F250 company truck, but the way it wallows around corners (kind of like a Cadillac Biaritz from the late '70s); I’m betting that, with the steel camper shell loaded with racks, the loaded ladder rack on top of the camper shell, and all the crap I haul around in it… I’m guessing that 7800 lbs isn’t all that far from max recommended gross.
And its 5.4L 3-valve engine’s “performance” bears ZERO resemblance to the one in the Ford GT -and d@mn little to the old 5.4 two-valve in my F150. It gets passed by little old snowbird ladies in Chevy Cavaliers and SmartCars at stoplights and the cam timing doesn’t really kick in until around 3500RPM. A freshly charged Prius wouldn’t be challenged by this truck.
But the A/C can ice the truck down to “hang meat” temperatures on a 115 degree day like today; and that’s all that matters to me from now until at least late September.