Bleeding of the Hydroboost- series of steps
04-27-2017, 09:40 PM
#1
Registered User
Thread Starter
Bleeding of the Hydroboost- series of steps
Need assistance on the HB installers, as I'm questioning Tallon's instructions. Their instructions are well written, and very specific as to what steps follow the next. The part I'm questioning is the brake bleeding. Midway thru the instructions, about the Master Cylinder, it says bench bleed, connect to booster, connect all hard lines, misc. electrical, then bleed entire brake system. This means, depressing the pedal(pump action)
From there, it goes thru the connections of all hydraulic lines that encompass the HB system. Then it says fill the PS fluid reservoir, and go thru the steps of burping out the system.
During the turn the tires back and forth part, it specifically says, do not depress the brake pedal, as possible damage may occur to the accumulator, until all air is out. It goes thru some more steps, then about two steps from the last instruction it tells you to depress the pedal, for the final PS fluid bleed and system check.
So, how did you all bleed your brakes w/o the HB assist in line? What steps did you all go thru?
Thanks, all
From there, it goes thru the connections of all hydraulic lines that encompass the HB system. Then it says fill the PS fluid reservoir, and go thru the steps of burping out the system.
During the turn the tires back and forth part, it specifically says, do not depress the brake pedal, as possible damage may occur to the accumulator, until all air is out. It goes thru some more steps, then about two steps from the last instruction it tells you to depress the pedal, for the final PS fluid bleed and system check.
So, how did you all bleed your brakes w/o the HB assist in line? What steps did you all go thru?
Thanks, all
04-28-2017, 03:48 PM
#3
Registered User
Here's my bleeding procedure, and errors I made.....
Originally Posted by thrashingcows
So I had some time today to swap out the PS pump....well at least that was what I was going to start with since I still had a spare Vacuum pump/PS set-up. It was actually the original set-up from my 93 motor, but I had converted my 89 motor to the IC style set-up and rebuilt the Vacuum pump, so that was what I swapped onto the 93 before it went in the crewcab. The original set-up from the 93 still had a painted date code of Oct 20/1992 on the PS pump!
I swapped it on, "T" the return line and then primed the system. Fire it up and all seems well. Took it for a good drive and no issues. The temperature of the PS lines was significantly less as well.
So a little info about priming the system after a PS pump, PS box or hydroboost change. Over the last couple days I have been doing some reading and research about priming the PS system properly. I'm pretty sure I am the reason the PS pump failed.
Here's What I did,
- fill the reservoir, then remove the power to the FSS and crank the motor for about 10-15 sec, then check the fluid again.
- Then I fired it up for about 10-15 seconds, shut it off and check fluid again.
- Then fired it up again and this time turned lock to lock with wheels off the ground. Took quite a while to finally get hyd pressure through the system.
It was during this air lock situation that I think the pump burned up the seals.
Now after my research I came across a few references to this procedure.
-fill the reservoir with fresh fluid. DO NOT START THE MOTOR! Then with wheels off the ground "slowly" crank the wheels lock to lock (LH and RH). Then check fluid level.
-Continue lock to lock slowly, checking the fluid after each cycle. I did this 10 times (LH to RH and back).
-Then I unhooked the FSS and cranked the motor for about 10-15 sec. Checked the fluid level.
-Did another 5 lock to lock cycles, checking fluid level.
-Crank motor again (FSS unhooked) for another 10-15 sec.
-Then another 5 lock to lock cycles.
-Fired motor up and cranked lock to lock 5 times, checking fluid.
-Dropped wheels back on the ground and everything was smooth as silk.
So far so good, so Will give it a week or so before purchasing a new PS pump for a 2nd Gen with hydroboost.
__________________
I swapped it on, "T" the return line and then primed the system. Fire it up and all seems well. Took it for a good drive and no issues. The temperature of the PS lines was significantly less as well.
So a little info about priming the system after a PS pump, PS box or hydroboost change. Over the last couple days I have been doing some reading and research about priming the PS system properly. I'm pretty sure I am the reason the PS pump failed.
Here's What I did,
- fill the reservoir, then remove the power to the FSS and crank the motor for about 10-15 sec, then check the fluid again.
- Then I fired it up for about 10-15 seconds, shut it off and check fluid again.
- Then fired it up again and this time turned lock to lock with wheels off the ground. Took quite a while to finally get hyd pressure through the system.
It was during this air lock situation that I think the pump burned up the seals.
Now after my research I came across a few references to this procedure.
-fill the reservoir with fresh fluid. DO NOT START THE MOTOR! Then with wheels off the ground "slowly" crank the wheels lock to lock (LH and RH). Then check fluid level.
-Continue lock to lock slowly, checking the fluid after each cycle. I did this 10 times (LH to RH and back).
-Then I unhooked the FSS and cranked the motor for about 10-15 sec. Checked the fluid level.
-Did another 5 lock to lock cycles, checking fluid level.
-Crank motor again (FSS unhooked) for another 10-15 sec.
-Then another 5 lock to lock cycles.
-Fired motor up and cranked lock to lock 5 times, checking fluid.
-Dropped wheels back on the ground and everything was smooth as silk.
So far so good, so Will give it a week or so before purchasing a new PS pump for a 2nd Gen with hydroboost.
__________________
04-28-2017, 04:06 PM
#4
Registered User
Thread Starter
You're on top of it, Brian. Thanks a bunch!
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thrashingcows (04-28-2017)
04-28-2017, 05:53 PM
#5
Registered User
Thread Starter
Forgot to mention, I saw your reply last night, on your tread, so that means I found it. Yeah, I don't want to cook off my new reman. Not worried about frying it, as it has a lifetime warranty on it. It's the R&R I don't want to go thru, LOL.
Brian, last one for this tread request- if all I did was remove my existing master cylinder, bench bleed and install the new one, and tie in the lines, do I need to crack the bleeders at the calipers and drums? I was wondering if maybe the proportioning valve on the 93 model year( prop valve directly under the master cylinder) has a check valve of some sort.
I hate bleeding brakes at the wheels! Mainly cause I'm at it myself, back and forth. I know- whining!
Brian, last one for this tread request- if all I did was remove my existing master cylinder, bench bleed and install the new one, and tie in the lines, do I need to crack the bleeders at the calipers and drums? I was wondering if maybe the proportioning valve on the 93 model year( prop valve directly under the master cylinder) has a check valve of some sort.
I hate bleeding brakes at the wheels! Mainly cause I'm at it myself, back and forth. I know- whining!
04-28-2017, 05:55 PM
#6
Registered User
Thread Starter
Reason I ask, is some trucks do have a check valve of some sort, and no bleeding of the wheel cylinders necessary on these, just the master getting bench bled is all that's required.
04-28-2017, 07:40 PM
#7
Registered User
I did not bleed the whole system when I installed my HB set-up. Just let the MC system gravity bleed by the junction block...left the fittings loose enough to allow air and fluid to pass. Let them sit like that of an hour or so and then tightened them up....no problems. 
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bigragu (04-28-2017)
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04-29-2017, 09:26 AM
#8
Registered User
There aren't any check valves unless the master cylinder is below the calipers then there would be light (2 lb.) residual valves to keep the fluid from bleeding back and the calipers retracting. My race car has these because the MC is below the floor.
If it had check valves the fluid wouldn't return to the master cylinder and it would keep the pads applied eventually building up enough pressure to lock the brakes up. Same thing happens if the master cylinder piston doesn't fully return. This is why the pushrod to master cylinder has to have some clearance.
I
If it had check valves the fluid wouldn't return to the master cylinder and it would keep the pads applied eventually building up enough pressure to lock the brakes up. Same thing happens if the master cylinder piston doesn't fully return. This is why the pushrod to master cylinder has to have some clearance.
I
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