Hard Brake Pedal

[RoyDaGeneral]

I recently changed my front brake pads and rotors. I've noticed over the last couple of weeks that brake pedal is hard in the morning, but not every day, maybe every 3 days or so. I did some online research and most point to a brake booster being bad. I did a test where you pump the pedal while car is off until it gets hard, then you start engine, and in my case pedal softens and drops once engine is started, which points to booster being fine. Any other ideas!

[brickbox]

I went through the same earlier this year on my '02 QX4. It's the brake booster hose (the check valve is integrated in our vehicles inside the hose). P/N# 47471-5W600.
It's a 5 minute replacement and you should be good to go.

[RoyDaGeneral]

I went through the same earlier this year on my '02 QX4. It's the brake booster hose (the check valve is integrated in our vehicles inside the hose). P/N# 47471-5W600.
It's a 5 minute replacement and you should be good to go.

Thanks a lot for the info. Is it easily accessible?

[RoyDaGeneral]

I purchased the hose from an online dealer. It looked like this one in my truck.

[brickbox]

Yep, that's the one.
Just be careful when taking that plastic retainer around the hose off. They seem to be very brittle and fall apart.

[R50JR]

I purchased the hose from an online dealer. It looked like this one in my truck.

You needed a brake fluid flush yesterday. Looks like dirt in there!

[yeldogt]

fluid is dirty ---- have it flushed

[RoyDaGeneral]

That's the project this coming weekend! It's been on my check off list. Would 1 quart of brake fluid be enough to do the 4 sides?

[macgiver]

Seeing that photo - Do they make "Brake system Flush" ????

Seriously , you need to take like a Turkey Baster , and SUCK as much of that "stuff" out of the rsvr. Just down to where the bottom holes/ action is still covered, and pre-fill with NEW fluid , yeah that's the ticket. Now when you bleed , you have fresh fluid immediately flowing , ya know .

Next time you goto the mud boggs - zip tie a plastic bag around that m/cyl . !!!

[RoyDaGeneral]

Well taken, I've had the truck for about a month now and only have Saturdays to do the work while learning all about it. I will get another quart of brake fluid in case I needed to do 2 flushes;)

Can you tell me how not to introduce air into system while I have my buddy pumping the pedal! Yes, I'll get as much out of the resvr as I can, then fill with fresh fluid. I guess to try to time it so that closing the valve takes place as soon as fresh fluid is coming out?

[macgiver]

Do like this :TELL buddy - "pressure" = foot on brake 15 LB pressure . TELL buddy - " 1,2,3, PRESS" = medium to heavy ,"follow-thru" , limit travel on buddy's foot to NOT BOTTOM OUT ! You will have opened the bleeder on three. You now close the bleeder when seeing fluid wane . TELL buddy " HOLD it" as you confirm bleeder is CLOSED , TELL buddy " release" = relatively slow let-up of pedal , and full release by buddy.
Begin " CYCLE " again with buddy , TELL buddy "pressure" ..... so on...
This is like one cycle , takes many . You go around , manual may say crisscross to other wheels - check that. Tapping the calipers sometimes accelerates the air to rise for more THOROUGH & quicker bleed results - 3rd buddy maybe necessary ,for tapping is best done AS YOU OPEN THEN CLOSE BLEEDERS ; difficult for one person ?

Do check the m/cyl for refilling you'll have to be doing , I have occasionally almost let it go too far down,myself

[RoyDaGeneral]

Awesome, thanks a lot, you wanna be the third buddy;)

[macgiver]

You become Roy DA Five-Star General of the Motors , yes Sir !

See how much FUN this car stuff is ??

[RoyDaGeneral]

At this point, I have yet to earn my first star, and having a blast too!

[yeldogt]

Do it in the proper sequence .. the time to do it was when you were working on the brakes?

Also -- the pump method can be problematic. I always use a pressure bleeder -- you can actually make one with a cheap landscape sprayer and extra fluid cap.

If trying the pump method -- don't go crazy pumping. Short pedal movements -- no deeper vs what would normally occur. Suck out old fluid fill and follow bleed rotation. farthest wheel first -- until clean. move to next ... On big bottle should be enough.

keep topping up as you pump ....

[RoyDaGeneral]

Yesterday my buddy stood me up, so I had no one to help me, I went to Harbor Freight and picked up their pneumatic brake fluid bleeder. I attached it to my compressor, and off I went. Limitation of that bleeder is you really can't tell when fluid becomes "airless," so I kept on bleeding until fluid became clean. I must have used 1.5 bottles of brake fluid. It was a little involved using the compressor and all the prep, but it worked out fine.

[yeldogt]

I have never used the HF -- the pressure bleeder I'm talking about have a hand pump. I have the $60 Motive. A shop would fill the Motive tank with fluid and let it go -- I just use it to pressurize the system and refill the cars tank. I don't want to have the hassle of cleaning the Motive.

That's why I said some make them -- if you google you will see.

As long as you did the bleed at each wheel until clean and no bubbles -- good to go.