Complete change of rake fluid (2005 AWD Astro)

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VanGeorge
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Complete change of rake fluid (2005 AWD Astro)

Post by VanGeorge »

I have never fully replace all the brake fluid in a vehicle. My Astro has 70K miles and inside the fluid container it looks like "zillions" of micro-micro something!
What is the best procedure to do a full flush.
I replaced the rear disc pads yesterday and that's when I saw inside the brake reservoir.
My plan was to replace front disc pads today and maybe flush the entire system when I was done with the brakes.
Is there an inexpensive something that I can hand pump or use the air compressor (what PSI setting) to speed up the process?
Thanks!
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HPbyStan
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Re: Complete change of rake fluid (2005 AWD Astro)

Post by HPbyStan »

I don't know how common these systems are but my friend @ LB Automotive in Ft Atkinson, Wi. has a power bleeder that is the same as the factory uses. It clamps to the master cylinder with the caliper bleeders open and and is under pressure and you just go around shutting them same as on the assembly line. Fresh fluid everywhere. I never asked him how much pressure, sorry...Stan
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VanGeorge
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Re: Complete change of rake fluid (2005 AWD Astro)

Post by VanGeorge »

Thank You Stan!
I've done a lot of surfing and found a Harbor freight model for $25. I'm going to look at it tomorrow and if they do not have one, I may build one.
There are a lot of posts and video's of home made ones. My problem is I need it fast.
I replaced the rear disc's on my 05 Astro AWD and got them way too tight. I have not found out how to properly adjust them so it will sit until I do....then I need to replace the front pads.
I still have my old backup 1987 Astro that I ordered back then. Probably the longest kept vehicle I have ever had in my life....soon to be 30 years "Young".
Thanks Again!
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Re: Complete change of rake fluid (2005 AWD Astro)

Post by HPbyStan »

Are the rear calipers on your ride free to move from side to side? Both my "gen3" Astros are problematic on me being able to keep the rear sliders free. Tried grease at first and now am trying that silver anti seize stuff. It may turn out they just need constant checking. The fronts don't seem to have that problem.
'04 White AWD Astro cargo
'00 Astro / El Camino
'61 BSA Super Rocket
'71 BSA B50 engine in a '67 C25 250 chassis
Impossible is just a degree of difficulty....
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Re: Complete change of rake fluid (2005 AWD Astro)

Post by VanGeorge »

I haven't done anything on it today. I hope it will be warmer tomorrow and I am going to take the rear wheels off and play with the adjustment. There is a 12mm hex head bolt going into the caliper hole AND there is a small bushing like tube that also has threads inside of it. It took me a while to figure this out. You have two very small flat spots on this bushing to put an open end wrench to remove and replace the bolt through it. But just how tight or how far the bolt is supposed to be threaded into the bushing until bolt reaches maximum depth is my problem.
When removing the bolt I must have turned it 50 revolutions and wondered why it was so tight AND did not come out like I'm used to the old Chevy's 3/8 allen tool.
After I discovered this "flat" area I piddled with it some and the bolt was almost loose enough to bring out with my fingers.
I'll let you know what I am able to do or find out. #-o
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Re: Complete change of rake fluid (2005 AWD Astro)

Post by HPbyStan »

VanGeorge wrote:I haven't done anything on it today. I hope it will be warmer tomorrow and I am going to take the rear wheels off and play with the adjustment. There is a 12mm hex head bolt going into the caliper hole AND there is a small bushing like tube that also has threads inside of it. It took me a while to figure this out. You have two very small flat spots on this bushing to put an open end wrench to remove and replace the bolt through it. But just how tight or how far the bolt is supposed to be threaded into the bushing until bolt reaches maximum depth is my problem.
When removing the bolt I must have turned it 50 revolutions and wondered why it was so tight AND did not come out like I'm used to the old Chevy's 3/8 allen tool.
After I discovered this "flat" area I piddled with it some and the bolt was almost loose enough to bring out with my fingers.
I'll let you know what I am able to do or find out. #-o
If the "slider" wont come out, thread the bolt back in, grab on it with a vice grips or like that and then hammer against that and it will eventually come out depending on how stuck it is. I cleaned the slider shaft on a wire wheel but on one of them I had to put a rotary grinder bit in an electric drill to grind the rust out of the "receiver". There is a rubber baffle around that assy, I don't know why it is so ineffective at keeping it free. If you got to turn it 50 turns, it probably isn't stuck and you won't have too much trouble removing it. O:)
'04 White AWD Astro cargo
'00 Astro / El Camino
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'71 BSA B50 engine in a '67 C25 250 chassis
Impossible is just a degree of difficulty....
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Wiley
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Re: Complete change of rake fluid (2005 AWD Astro)

Post by Wiley »

I know you said you need it fast, but I am a fan of using a 2x4 and pumping the brakes solo, that way I always know what is going on as there is only 1 idiot working on my van, rather than several. I have speed bleeders I am going to try next time I mess with my brakes, those sound like a good fix as well.


Also I have read some people can have a problem with pressure bleeders tearing the seal in the master cylinder, while others use the pressure bleeder without any issues, something to keep in mind.
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Re: Complete change of rake fluid (2005 AWD Astro)

Post by VanGeorge »

Hey guys, thanks for the tip about the slider and the "Heads Up" about the pressure bleaders.
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Re: Complete change of rake fluid (2005 AWD Astro)

Post by Smiliesafari »

Pressure bleeders only need 4-5 psi to work. Far less pressure than when you apply the brakes.
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Re: Complete change of rake fluid (2005 AWD Astro)

Post by WoodButcher »

Wouldn't a vacuum bleeder kit work just as well?
One wheel at a time and keep the reservoir full.
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Re: Complete change of rake fluid (2005 AWD Astro)

Post by Smiliesafari »

Yes, it would work just fine. The advantage of the pressure system is the constant supply of fluid.
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Re: Complete change of rake fluid (2005 AWD Astro)

Post by VanGeorge »

Well, I finally got around to making the swap of all four wheels brake disc's but now my problem is that I have constant pressure being applied to the rear brake.
I got the calipers back into their nest but when I released the c clamp they wanted to push out so getting them on was a bit frustrating for both rear pad sets.
I drove it about two miles several days ago and you could smell the brake "odor" from being applied somehow.
Does anyone have a clue as to why this is happening? I have spent way too much time on what should have been a 2 to 3 hour job. (at my slow speed)
I am concerned about this and will not drive it until I know its working properly.
Someone Please tell me that someone on these forums has had the same problem and the hopefully "easy" fix and send me an e-mail. (or your phone number and I will call you) ](*,)
Thanks
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Re: Complete change of rake fluid (2005 AWD Astro)

Post by HPbyStan »

Is the master cylinder too full ?
'04 White AWD Astro cargo
'00 Astro / El Camino
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'71 BSA B50 engine in a '67 C25 250 chassis
Impossible is just a degree of difficulty....
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Re: Complete change of rake fluid (2005 AWD Astro)

Post by VanGeorge »

Checked the master cylinder, the fluid is appx 1/8" above the bottom in the front area.
I also backed up the nut on the parking brake to see it that had any effect and found none at all.
I am at a standstill here, I do not want to drive the vehicle with the rear brakes "applied" by something mysterious and causing it to possible warp my rear discs.
When removing the 12mm bolt, does the slider "need" to come out also and does it slide out the same hole that the bolt goes into?
When I replaced the pads, I did not remove the four "tubes" that the bolt goes through to hold the calipers in place.
Thanks for the input you guys, if I find the solution, I will gladly share.

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Re: Complete change of rake fluid (2005 AWD Astro)

Post by LiftedAWDAstro »

Lets see if you are getting fluid pushed to the calipers or is it a mechanical bind. Without pressing the brakes, jack the van up, remove both back tires and loosen the caliper bleeders. If you get a little fluid out then they probably are not under pressure. If it sprays out with some force, you got pressure either being applied or held. Could be one of the rubber lines holding pressure if this is the case. Also throw up a bunch of pics if you can.
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