How well do the brakes on your cucv work?

[jimmy-90]

Hello I just replaced the fluid in my master cylinder and bled all four brakes. I used D.O.T. 5 brake fluid and a mytivac bleeder. I was able to get all the old fluid and air out of the lines but it didn't really help too much. For some reason when I do a panic stop like when the light turns yellow and you can either floor it or punch the brakes, the petal will reach kind of a breakover point and hit the floor. Like I say to make it do that you have to jam on the brakes very suddenly though. Also I never have been able to lock the brakes up and skid with this truck. My question is does everyone elses powersteering pump driven brakes on their cucvs do these types of things or is something wrong with my braking system?

 

[Westech]

you have a problem. Hydro boost brakes should lock up all 4. You need to go thru your brakes and make sure, #1 hardware is good and calipers move free, pads and rotors are with in specs, drums are not over sized and shoes are with in spec along with good hardware in the rear. you may also have a master cylinder issue.
Time to hit the books if you do not know what you are doing.

 

[kassim503]

I think you may still have air in the lines, usually if you hit a flatline in pedal pressure, its the air compressing over the fluid. The mityvac dosent get the lines bled out very well sometimes, try doing the 2 person method.

 

[Timber]

When you can 'push through' a firm spot in the brake pedal you've generally got a master cylinder gone bad.

 

[jimmy-90]

Im pretty sure all the air is out of the lines. Me and my father both made extra sure of that because that is what we originally thought was wrong with it. And yeah that is exactly how it feels. Like there is air in the lines. It had crossed my mind that the master cylinder might be bad. Do you guys think that a week power steering pump could make it do that? When I hit the brakes that way you can hear it strain the motor a little.

 

[motormayhem]

On my m1009 I can push it down to the floor and the last 1/4 of travel feels different than the first part, but it can lockup the tires in a panic situation with ease and i am running bigger rear cylinders because it has a 14 bolt in the rear. When cars in front of my slam the the brakes to not go though a yellow I can lock up those 36" tires on a dime and make them scream.

 

[Milbikes]

If your power steering works ok, the pump is probably not the problem. Sounds like master cylinder seals failing. If the old fluid looked like coffee, the 'solids' came from somewhere.

 

[DXTAC]

My money is on the master cylinder. My problems were very similar. I replaced the master cylinder, rear shoes, drums, wheel cylinders and bled the entire system. Now all is good! A master cylinder is only about $35.00 at Napa. Brake parts are cheap on these!

 

[91W350]

All three of mine will lock up. My M1008 almost has too much brake running empty. Especially the first few stops on a moist morning.

 

[kipman]

My 1009 has great breaks, same they are touchy when wet.

 

[jimmy-90]

If your power steering works ok, the pump is probably not the problem. Sounds like master cylinder seals failing. If the old fluid looked like coffee, the 'solids' came from somewhere.

My power steering is pretty stiff when im sitting still but it doesn't seem to leak or squeal. You gotta be moving a little to get it to steer. And also I didn't realize that a new master cylinder was so inexpensive!!! Thats great news. But if it is my powersteering pump im pertty sure that will cost a bit more than $35.00. Are any of you guys running a bad or semi-bad powersteering pump with good working brakes?

 

[Barrman]

The pedal should never go to the floor. Engine off, booster not charged and your pedal should not hit the floor. You have a brake problem that is more than likely master cylinder related as posted above. Get a new, not rebuilt one, bench bleed it, (I like to install it on the truck and "bench bleed" on the truck so less fluid is dripped on stuff.) and see what you get.

If you look at the -20 for brake bleeding it states you have to block off the proportioning valve piston when bleeding or it will think you have a leak and cut off pressure to either the front or back depending on which end you are bleeding. Pressure bleeding is a great way around this and a great way to bleed. However, if you have the system bled now and properly bench bleed the master, you won't need to bleed the system again.

Now, once you have done that and the pedal still has no firm stop to travel and keeps going down slowly with the engine on or off. Then you have a leak somewhere else. Only when that is resolved do you really need to look at the Hydroboost system. It is a brake helper, not a brake applyer. The booster takes you from using your entire leg like at the gym to lock up the tires to a big toe wiggle to lock them up.

 

[rnd-motorsports]

Perfect could not have said it better!! Barrman stated it perfect!!!

 

[BIG_RED]

My M1009 breaks work awesome. Better than my vac assisted vehicles. They did not change much when my Power Steering pump went bad (just less power assistance). You for sure have a master cylinder / break lines problem. One time, a kid ran out in front of my truck. I slammed the breaks as hard as I could. I was going about 35 mph. Unloaded. Pretty sure I stopped so hard, my back end lifted off the ground (just guessing cause it was loud when it came back down). All tires locked up (33's), loud as ****. Kid about cr@ped his pants. But I didn't hit him.

 

[Barrman]

Yes, my M1009 brakes are awesome. The best of any vehicle I own.

 

[BIG_RED]

Just don't hit the breaks on ice short wheelbase M1009 will do about a 9000* rotation if your steering wheel is not perfectly straight Thankfully, the 4x4 with rear locker will get you out of the ditch. (can you tell I've done this before )

 

[Timber]

I hate to be the bearer of bad news, but master cylinders seems to be one of those parts that you may buy new, but it may not be worth a ****. We're getting so much chinese junk passed off as parts and shelved in inventory of parts stores that it's a wonder we can fix anything anymore. I've read threads of guys going through a few before they finally install one that is works.

Keep in mind, that's not calling it a quality part. Only that it worked.

I hope your luck is better.

 

[Croatan_Kid]

The brakes on my M1008 work great. I'm also running hydro-assist steering....that poor power steering pump! I can lock up my 40s if I have to, but it's usually pretty scary if it gets that bad.

 

[Seabee15]

When ever my brakes are a little wet, they get very very touchy...To the point where a wheel will lock up if i try to slow down to a stop going 20mph to 0mph....

not sure if this is bad...I am slowly redoing the entire truck, brakes are next on list.

 

[rnd-motorsports]

I wish the brakes on my 2500hd same system but with 4 wheel disc worked or stopped as good as the 1028!