Random hard brake and clutch pedal

[blackmav]

GQ Td 42 1990 wagon

I keep getting a random hard brake and clutch pedal feel. Sometimes reversing out of the drive the brake pedal gives no stopping power and is hard, also happening out wheeling (not good).
I also think a similar thing is happening with the clutch but even more random.
I have replaced the slave cylinder on the brakes due to a bit of weeping onto the booster.
Could it be a vac prob and how do I diagnose the fault?

[CruiserPatrol]

remove vac hose and test drive slowly in the drivway, see if that is how it feels when you get a hard one. then with the engine running stick your finger over the vac hose to see if it sux. I think you are right in thinking it is a vac problem considering it is effecting the clutch and brake.

Do they both display these sympoms at the same time?

Dave

[stool]

I also have the hard brake out wheeling. And somtimes need to use the
hand brake to stop me from moving backwards down the hill.

I will be looking for a vac leak.

[michael a]

Same problem mine comes when holding clutch half down

[canuck]

Yes, check the vac pump with a vac gauge. If you don't have one, then you can buy or rent one at most auto part stores. I can't find my manual (probabbly buried under something in the shop) but somone should be able to tell you the correct vac should be. It could be that your vac pump is worn and not providing enough vac when you need a lot of it: clutching, braking and steering at the same time. If it is not the pump, then you will have to check all vac lines for a leak. Make sure you tag each line after you have checked it, or if you're like me, you might find yourself checkin the same line twice. But start with the pump, as it is the easiest place to start. Good luck,
John

[canuck]

Found the Haynes manual but can't find any numbers on the amount of Vacum the pump should be producing. Hopefully somone else on the forum will have that info for you.
John