Changing Brake fluid

[TommyL]

Hi guys, I want to change my brake fluid again but this time I would like to run the anti lock module as well to get fresh fluid into that unit. Anyone have a trick to run the anti lock to get fresh fluid throughout the entire system? As well any suggestions on what fluid to use? I have been using a German make that seems to work very well in the Z but just wondering what you guys are using.

[Flyman 27]

I used a simple power brake bleeder to push all the old stuff thru the system. It worked well.

https://www.amazon.com/gp/product/B00CJ5DWKO/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

[TommyL]

Ahh ok, I have been manually pushing it through but have access to a power unit. If that works great!

What kind of fluid is everyone using in the brakes, trans and rear end these days? I know years ago the BMW fluid was all the rave as well as Castrol for the trans and rear end. I'm sure things have changed somewhat, what is best now a days?

[Paul Workman]

I used a simple power brake bleeder to push all the old stuff thru the system. It worked well.

https://www.amazon.com/gp/product/B00CJ5DWKO/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Details, details.... What tool are you using? And, some pix would be nice!;):cheers:

[secondchance]

TommyL,

If you want to flush brake fluid compleltly including ABS pump, I believe you need Tech 1. I never tried this method.
As for the fluids, I am using Pentosin DOT 4LV brake fluid, Castrol Edge synthetic 10-60 for trans and Mobil 75-90 with GM limited slip additive.

[TommyL]

These fluids are what I used in my 90 for years. I thought maybe there have been some changes but still using the same quality fluids.. a good thing. I remember years ago hearing that you needed to cycle the ABS to get the fluid flowing through it, I also recall someone saying there was another way to cycle the ABS pump without a Tech 1. Hmm might have to look into this a little more as I would really like to get fresh fluid through the entire system. I can see a power flush pushing the old fluid through the ABS unit but seems no one can confirm that.


:cheers:

[secondchance]

My understanding of the abs system is that, with abs valve shut, power flush will not push new fluid through abs unit. When the brake pressure is induced, resulting pressure goes to all 4 corners until a wheel lock up is detected at which time abs bypass the pressure to locked up wheel releasing the brake momentarily. Once locked up wheel rotates again, brake pressure is reengaged.
Every time the car is started, growling noise you hear, I believe, is abs pump and valves cycling to verify proper function. I believe, when this happens and also when you trigger abs, for example braking on ice or snow, fresh fluid moves through abs system. For this reason, I think, fluid inside abs is continually cycled.
For those with patience, below link will take you to abs-asr system explanation and hydraulic system schematic.

http://www.lwta.net/photos/Corvette%20C4%20ABS-ASR%20Operation%20and%20Diagnosis%20Manual.pdf

[Hib Halverson]

Some EBTCM's support bleeding via scan testing. If your EBTCM does support that, using the function is the only way to completely flush and bleed the system.

Follow the service manual procedures for beeding listed in the FSM for your model year.

[Jagdpanzer]

look around in my 1994 FSM and found nothing mentioned about using a Tech 1 scanner for flushing and bleeding the brake system.
So I rigged up a pressure bleeder from $10 one gallon sprayer from Home Depot 11899


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[Mystic ZR-1]

look around in my 1994 FSM and found nothing mentioned about using a Tech 1 scanner for flushing and bleeding the brake system.
So I rigged up a pressure bleeder from $10 one gallon sprayer from Home Depot 11899


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Sounds like a great idea!
How did you connect it to the reservoirs on the master cylinder?

[Jagdpanzer]

Installed a hose fitting in a replacement Dorman cap picked up at a local auto parts store.
11914


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[Mystic ZR-1]

Thanks!
Would have to figure out a different way on a 90 due to 2 push on caps for the MC reservoir?
Dorman probably has something that would work?