Final 1152 brake bleeding

[Dave2018]

Open to suggestins on this job.
Replaced power steering pump and hydroboost. Both oem AMGeneral bought.
PS is fixed. No noise and smooth. Think air still in brakes. Have bled the mc twice using the dorman fittings and hoses. No air left that is seen. Bled wheels twice also. Never got much air out of them.
The problem is the pedal is a little hard to press and then it grabs but takes a little before fully releasing. Using all Dot 5 in my 1152. Its like it has to push past a certain the grabs instead of a smooth grab from the start.
Thanks for any ideas.

 

[Mogman]

Open to suggestins on this job.
Replaced power steering pump and hydroboost. Both oem AMGeneral bought.
PS is fixed. No noise and smooth. Think air still in brakes. Have bled the mc twice using the dorman fittings and hoses. No air left that is seen. Bled wheels twice also. Never got much air out of them.
The problem is the pedal is a little hard to press and then it grabs but takes a little before fully releasing. Using all Dot 5 in my 1152. Its like it has to push past a certain the grabs instead of a smooth grab from the start.
Thanks for any ideas.

Was it the same before and after replacing the hydro-boost? was there any sign of contamination in the master cylinder?

 

[Dave2018]

Was it the same before and after replacing the hydro-boost? was there any sign of contamination in the master cylinder?

Only difference in fluid is different shade. Only mil and civ dot 5 fluid used.
Dont know that old boost was bad but replaced it after 2nd ps pump didnt fix noise..ect.
Dont see any contamination in fluid. Some not crystal clear but not full or air.
Brakes did get air but have bled a lot and no air. Looking for a bleeder screw on boost but think maybe only the high pressure line for a bleed.
Thanks
Dave

 

[Mogman]

Only difference in fluid is different shade. Only mil and civ dot 5 fluid used.
Dont know that old boost was bad but replaced it after 2nd ps pump didnt fix noise..ect.
Dont see any contamination in fluid. Some not crystal clear but not full or air.
Brakes did get air but have bled a lot and no air. Looking for a bleeder screw on boost but think maybe only the high pressure line for a bleed.
Thanks
Dave

No bleeding of the hydro boost is needed.
Are you getting a good stream when bleeding all 4 calipers?

 

[Dave2018]

No bleeding of the hydro boost is needed.
Are you getting a good stream when bleeding all 4 calipers?

Pretty solid steady stream. Do you think a messed up ps pump could mess up the hydroboost..it dosent seem like it should. Have bled the mc again, no air.
When I press the brake pedal with my hand I can feel a little mechanical resistance before it starts going down. Kind of weird for a new boost.

 

[Dave2018]

Pretty solid steady stream. Do you think a messed up ps pump could mess up the hydroboost..it dosent seem like it should. Have bled the mc again, no air.
When I press the brake pedal with my hand I can feel a little mechanical resistance before it starts going down. Kind of weird for a new boost.

And it didnt have that resistance before this job started.

 

[Retiredwarhorses]

What model truck? ECV or REV?
the REV uses a different MC and hydrobooster then the ECV…

 

[Dave2018]

What model truck? ECV or REV?
the REV uses a different MC and hydrobooster then the ECV…

Hello, this isn't the rev, its the 1152A1. I have re bled the mc a couple times and re bled the 2 what I call high point bleeders coming off the mc line assembly's I also re bled all four wheels. I am not getting any air. Only help I can fine is that when system is off I can push the brake pedal and the first 1/4" or so feels like metal movement before it goes smooth. It still is grabbing some just after that first 1/4". Maybe I messed up my boost with the bad pump on it. Still using my original mc, truck less than 2k miles. Plastic was still on seats and gearshift when brought home.
thanks,
Dave

 

[mrandig]

Assuming the brakes are bled correctly, I'm thinking that what you're feeling is happening within the hydro boost unit (power piston or spool valve?). You may want to try bleeding your power steering again.

 

[Dave2018]

Assuming the brakes are bled correctly, I'm thinking that what you're feeling is happening within the hydro boost unit (power piston or spool valve?). You may want to try bleeding your power steering again.

I don't know which boost I have on it, was new a few months ago. Yes I will give it another good ps bleeding. Don't want to pull the boost again if at all possible.
Thx
Dave

 

[Mogman]

Hello, this isn't the rev, its the 1152A1. I have re bled the mc a couple times and re bled the 2 what I call high point bleeders coming off the mc line assembly's I also re bled all four wheels. I am not getting any air. Only help I can fine is that when system is off I can push the brake pedal and the first 1/4" or so feels like metal movement before it goes smooth. It still is grabbing some just after that first 1/4". Maybe I messed up my boost with the bad pump on it. Still using my original mc, truck less than 2k miles. Plastic was still on seats and gearshift when brought home.
thanks,
Dave

You may want to look carefully at the linkage under the dash, "feels like metal movement" sounds like possibly something is interfering.

I really do not see how you could damage the original hydra-boost with any type of pump failure with the one exception, if the pump came apart and contaminated the entire system with debris, in that case unless you completely dismantled the entire system (including the steering gear itself) and thoroughly flushed every system component then you still have a contaminated system.

 

[Retiredwarhorses]

Hello, this isn't the rev, its the 1152A1. I have re bled the mc a couple times and re bled the 2 what I call high point bleeders coming off the mc line assembly's I also re bled all four wheels. I am not getting any air. Only help I can fine is that when system is off I can push the brake pedal and the first 1/4" or so feels like metal movement before it goes smooth. It still is grabbing some just after that first 1/4". Maybe I messed up my boost with the bad pump on it. Still using my original mc, truck less than 2k miles. Plastic was still on seats and gearshift when brought home.
thanks,
Dave

An M1152A1 can be either an ECV variant or a REV variant, it’s important to know this because the serial number range dictates parts application between the two, the REV uses different MC and Hydrobooster….in the TM you want to pay attention to the UOC “use on code” next to the part number identification.

Next question: what color are the studs on the hydrobooster on the master cylinder side ? Blue or Orange

 

[Dave2018]

You may want to look carefully at the linkage under the dash, "feels like metal movement" sounds like possibly something is interfering.

I really do not see how you could damage the original hydra-boost with any type of pump failure with the one exception, if the pump came apart and contaminated the entire system with debris, in that case unless you completely dismantled the entire system (including the steering gear itself) and thoroughly flushed every system component then you still have a contaminated system.

This is true, I have not checked the linkage yet. will get that as soon as I get home.
thx
dave

 

[Dave2018]

An M1152A1 can be either an ECV variant or a REV variant, it’s important to know this because the serial number range dictates parts application between the two, the REV uses different MC and Hydrobooster….in the TM you want to pay attention to the UOC “use on code” next to the part number identification.

Next question: what color are the studs on the hydrobooster on the master cylinder side ? Blue or Orange

Blue studs, and I believe they matched color on studs of one removed. My takeout boost is probably just fine. But could not tell where the noise was coming from.
thx
dave

 

[Retiredwarhorses]

Blue studs, and I believe they matched color on studs of one removed. My takeout boost is probably just fine. But could not tell where the noise was coming from.
thx
dave

Where did you source the booster? Part number #

 

[Dave2018]

Where did you source the booster? Part number #

Where did booster come from... I believe it came from mac motors but I need to double check if its also from somewhere else and a chinese knockoff. working but with big cold, haven't touched truck a few days. Going to find where the boost came from though.

 

[Dave2018]

Where did booster come from... I believe it came from mac motors but I need to double check if its also from somewhere else and a chinese knockoff. working but with big cold, haven't touched truck a few days. Going to find where the boost came from though.

The hydroboost came from ILM Enterprise Int of dickinson texas. 395.34, I didnt know cheap charlie chinese was knocking these off. I may need to put my oem back on. going to check with them for AM General or charley manuf.

 

[Dave2018]

The hydroboost came from ILM Enterprise Int of dickinson texas. 395.34, I didnt know cheap charlie chinese was knocking these off. I may need to put my oem back on. going to check with them for AM General or charley manuf.

Got bit a little bit, Have used Dot 5 since my M151A2 trucks. got bit now for not reading more about the Dot 5.1 fluid. Could have saved a little trouble. I did mix my 5 with the 5.1. Going to remove all the fluid from lines and MC then flush really well with Dot 5 and refill with dot 5. And this may not matter huge but mentioning, The 1152A1 Hydroboost has 2 different numbers depending on the serial numbers. I ended up with the one for 299,999 and above but should have bought the one for below 299,999. Its been on the truck a while and never had an issue but may go back with my original take out. I believe the original problem noise was the PS but couldnt narrow it down and put new hydroboost on it.
I pulled half the engine off my older 998 and did a ton of work, it always turned out better that this hmmwv. Will update later.

 

[mrandig]

For the brake bleeding, I went over to Harbor Freight and got a new brake bleeding kit. It absolutely does make one-man flushing and brake bleeding so, so, so much easier. At Harbor Freight they're less than $30.00.

I highly recommend getting one, if you don't have it already.

 

[Retiredwarhorses]

Got bit a little bit, Have used Dot 5 since my M151A2 trucks. got bit now for not reading more about the Dot 5.1 fluid. Could have saved a little trouble. I did mix my 5 with the 5.1. Going to remove all the fluid from lines and MC then flush really well with Dot 5 and refill with dot 5. And this may not matter huge but mentioning, The 1152A1 Hydroboost has 2 different numbers depending on the serial numbers. I ended up with the one for 299,999 and above but should have bought the one for below 299,999. Its been on the truck a while and never had an issue but may go back with my original take out. I believe the original problem noise was the PS but couldnt narrow it down and put new hydroboost on it.
I pulled half the engine off my older 998 and did a ton of work, it always turned out better that this hmmwv. Will update later.

The SN range is 300k and above is REV, 299,999 and below is ECV, that’s why I asked…the 2 MC studs on a “true” OEM Hydrobooster are “orange, not blue, Blue is 299,999 and below, the correct part number is 12342899