GM Longroof Forum
Would you like to react to this message? Create an account in a few clicks or log in to continue.



 
HomeHome  PortalPortal  GalleryGallery  SearchSearch  RegisterRegister  Log in  

 

 Pressure Bleeding the brakes ?

Go down 
4 posters
AuthorMessage
AzDon

AzDon

Posts : 339
Join date : 2011-08-05
Age : 65
Location : Lake Havasu, AZ

Pressure Bleeding the brakes ? Empty
PostSubject: Pressure Bleeding the brakes ?   Pressure Bleeding the brakes ? Icon_minitimeSat Mar 28, 2020 9:23 pm

I did something stupid..... I allowed the brake fluid reservoir to get low enough on fluid that air got in the system, specifically the rear brakes..... I knew I was screwed because I don't have a helper with an hour or more available to pump the pedal, so I went to my OCC FSM to find out the secrets that the dealer would use to successfully power bleed the system...

I was already reasonably certain that a clamp-on bleeder lid would crack the reservoir before it was tight enough to seal...
The secret revealed in the FSM is a j29567 bleeder adapter kit.....It is essentially two stand-pipes fitted to the holes in the bottom of the reservoirs with a step holding an o-ring… the stand pipes each have two arms that a bungee assembly that straps under the entire master to hold the stand pipe(S) down against the o-ring(s) under 15 pounds of pressure....
The Kent-Moore j29567 is apparently out of production, but used setups start at $125 on ebay and may even be operational...

I decided to build my own!..... I found a couple of half-drive sockets in my inventory that fit the bores of those holes and they are tapered so a large flat washer could only slide up about an inch... Below the flat washer is a urethane garden hose seal and below that, an a/c oring…. Welded to the top of each socket is a 1/2" npt female plumbing fitting.... above that, the hold-down arm, a ball- valve, a plumbing t and another ball valve..... The fluid is plumbed into the side of the "T" below the top ball valve....The stand pipes are clamped down and the pressure pot is lightly pressured with all four ball valves open until all the air is bled out of the pipes and then the top valves are closed...…. then 15 pounds on the pot and the bleeding can begin ….

Oh, And the pressure pot?.... It is a one gallon weed sprayer from harbor freight that you hand pump after putting 2 quarts of fluid in it....It is adapted to hold pressure with 1/4 clear ice-maker hose as a down-tube and 1/4 inch crunch-ferrel hose and plumbing supplying the fluid to the down pipes..... I used all opaque ice-maker hose so I can see the absence of bubbles. The pump pot is also opaque, so you can watch the fluid level...

The rig worked perfectly as designed with zero mess or mishaps and I was able to get ALL of the air out of the right rear brake cylinder while losing only about 6 oz of fluid....
It's really nice to have my brakes working normal again!
Back to top Go down
http://v-driveboat.com
rcktpwrd

rcktpwrd

Posts : 368
Join date : 2019-03-06
Age : 47
Location : Raleigh, NC

Pressure Bleeding the brakes ? Empty
PostSubject: Re: Pressure Bleeding the brakes ?   Pressure Bleeding the brakes ? Icon_minitimeSun Mar 29, 2020 8:59 am

sounds pretty slick!

got any pictures to share?
Back to top Go down
AzDon

AzDon

Posts : 339
Join date : 2011-08-05
Age : 65
Location : Lake Havasu, AZ

Pressure Bleeding the brakes ? Empty
PostSubject: Re: Pressure Bleeding the brakes ?   Pressure Bleeding the brakes ? Icon_minitimeSun Mar 29, 2020 12:24 pm

I'm not a smart phone guy yet.... I did get pictures, but my focus was on getting the brakes bled, as these cars really don't stop that great with only the front brakes working...
I wanted to prove that the rig worked before posting anything about it and now I need to do some pic transferring and resizing so I can then figure out how to post them on this site....
In the end, all the plumbing fittings and the pump pot went well over $100, but I believe it will work on my 91 van and 94 dually also, so I just consider it a tool investment that was still cheaper than paying a shop just once for power bleeding...
It was a fun challenge to design and build a somewhat complex tool and see it actually work as designed!
Back to top Go down
http://v-driveboat.com
Fred Kiehl

Fred Kiehl

Posts : 6013
Join date : 2009-11-13
Age : 72
Location : Largo, FL 33774

Pressure Bleeding the brakes ? Empty
PostSubject: Re: Pressure Bleeding the brakes ?   Pressure Bleeding the brakes ? Icon_minitimeSun Mar 29, 2020 7:07 pm

You are fortunate that the master cylinder did not get air in it. To get the air out, you must bench bleed the master, so that it is level, or nose down to ensure the air does not have a pocket to remain in.
Back to top Go down
AzDon

AzDon

Posts : 339
Join date : 2011-08-05
Age : 65
Location : Lake Havasu, AZ

Pressure Bleeding the brakes ? Empty
PostSubject: Re: Pressure Bleeding the brakes ?   Pressure Bleeding the brakes ? Icon_minitimeSun Apr 05, 2020 2:45 pm

Pictures?Pressure Bleeding the brakes ? Powerb10
Pressure Bleeding the brakes ? Powerb11
Back to top Go down
http://v-driveboat.com
AzDon

AzDon

Posts : 339
Join date : 2011-08-05
Age : 65
Location : Lake Havasu, AZ

Pressure Bleeding the brakes ? Empty
PostSubject: Re: Pressure Bleeding the brakes ?   Pressure Bleeding the brakes ? Icon_minitimeSun Apr 05, 2020 2:59 pm

Pumping this setup by hand worked superfine and it maintained enough pressure to display all the fluid necessary....The one thing I will add before using this setup again is a couple of 1/4" hose barbs in the top ball valves with clear return hoses down into the reservoir.... The top ball valves are for bleeding all air out of the top of the bleeder rig after the pipes are tied down, but before any bleeding proceeds....I used as-is by opening those valves slightly and carefully while holding a rag above....
Back to top Go down
http://v-driveboat.com
94Woody

94Woody

Posts : 2038
Join date : 2008-12-02
Age : 46
Location : Belleview,FL

Pressure Bleeding the brakes ? Empty
PostSubject: Re: Pressure Bleeding the brakes ?   Pressure Bleeding the brakes ? Icon_minitimeSun Apr 05, 2020 3:01 pm

Wow, that's a lot but good job.

I just crack open a bleeder screw and let gravity do the the rest. They also make simple one man bleeders that involve a hose and a container one fills with brake fluid. Connect hose to bleeder and put other end in container and pump the pedal a few times.
Back to top Go down
Fred Kiehl

Fred Kiehl

Posts : 6013
Join date : 2009-11-13
Age : 72
Location : Largo, FL 33774

Pressure Bleeding the brakes ? Empty
PostSubject: Re: Pressure Bleeding the brakes ?   Pressure Bleeding the brakes ? Icon_minitimeSun Apr 05, 2020 3:19 pm

I bought the bleeders with a check valve. Open them and run a line to a bottle. Pump the brakes, and keep an eye on the fluid level in the master cylinder. Cost me $30.
Back to top Go down
Sponsored content




Pressure Bleeding the brakes ? Empty
PostSubject: Re: Pressure Bleeding the brakes ?   Pressure Bleeding the brakes ? Icon_minitime

Back to top Go down
 
Pressure Bleeding the brakes ?
Back to top 
Page 1 of 1

Permissions in this forum:You cannot reply to topics in this forum
GM Longroof Forum :: Longroof Tech :: Suspension, Steering and Brakes-
Jump to: