Flush your brake fluid!!

[swat2380]

Just did a complete brake job on new to me 07 Denali with 75k. I partially drained and filled the master cylinder via turkey baster 2x's a couple months before doing the brake job. I replaced everything in the brake system including new stainless hoses, drained the calipers and was still surprised at the rust, metal, and one rear caliper had nasty grey fluid almost resembling bad gear oil.

I am lucky enough to not live in a rust prone area where lines rust out etc. I do this on all my vehicles every 2 years or so and always get a nice performance difference in braking. A fluid flush will cost anywhere from $7-$16 bucks depending on what fluid you buy.

Our rides usually spec Dot 3 but you can use 4 or 5.1 safely, I used Castrol Dot 4. For a homemade bleeder setup I used a plastic fitting from a harbor freight bleeder kit and some clear hose fed into a RC car fuel bottle with a little fluid added to prevent air getting sucked back in. I would have preferred a larger hose over the bleeder nipple but didn't have one available. Cheap, easy, usually nice performance bump and keeps you and the family safe.

 

[iamdub]

Agreed. It's too easy and too beneficial to not do it.

 

[jmm121783]

i need to do this and flush my pumpkins, tranny and transfer case

 

[swat2380]

I also did the diff's at the same time however I didn't take the cover off the rear. I removed the fill plug and used a common gear oil pump to suck it out and jacked up each side of the axle tube to get most of the fluid remaining. Normally I would open it up, inspect, clean with brake cleaner etc. but it seems to be working fine and I plan to do this again in a couple months with a new cover that has a drain plug. Took about 20 minutes and much cleaner that way.

The front was a different story some dumba$$ stripped the fill plug and its not budging. Of course I noticed this after draining the old fluid. I decided to fill it from the drain plug after screwing with it over an hour. I just added some extra fluid to account for a little spillage and it worked fine.

Remember to use RTV made for gear/synthetic oil if you take the rear cover off if you cant reuse the factory gasket. I used RedLine 75w-90 in the rear and Mobil 1 75w-90 in the front since I had it on hand.

I did the transfer case and trans a couple months back. Used Castrol Dex VI for both and some LubeGuard Platinum. I did the transfer case again after about 500 miles since it came out a little dirty and its AWD.

 

[the blur]

You really like the SS brake hoses ? Are they DOT approved ?

 

[Rocket Man]

i need to do this and flush my pumpkins, tranny and transfer case

You're gonna flush your pumpkins?

 

[sk1dm4rk]

Old school term for differentials.

 

[wendal]

I've seen this service offered at different Lube shops and Firestone. Is it the same as what you're doing here? I can do pads and rotors, but opening up the brake fluid system is just something I've never wanted to attempt, as I remember my dad saying that getting air in the brake fluid system could be fatal... I'd also like to replace my hoses with braided metals. Did you do this all at once, or at different times? Are there detailed instructions out there somewhere, or should I just go and get it done and spend the extra $$? I'm fairly mechanically inclined, I've just been scared of brake fluid system. While I'm asking, has anyone ever had an issue where light braking in a turn produces a rub vibration in the brake pedal? Seems to be something like a caliper rubbing, but I cannot locate or identify it. Thanks in advance for all info!

 

[Rocket Man]

I've seen this service offered at different Lube shops and Firestone. Is it the same as what you're doing here? I can do pads and rotors, but opening up the brake fluid system is just something I've never wanted to attempt, as I remember my dad saying that getting air in the brake fluid system could be fatal... I'd also like to replace my hoses with braided metals. Did you do this all at once, or at different times? Are there detailed instructions out there somewhere, or should I just go and get it done and spend the extra $$? I'm fairly mechanically inclined, I've just been scared of brake fluid system. While I'm asking, has anyone ever had an issue where light braking in a turn produces a rub vibration in the brake pedal? Seems to be something like a caliper rubbing, but I cannot locate or identify it. Thanks in advance for all info!

Instead of paying somebody to do it, get a Motiv pressure bleeder and you'll be amazed how easy it is. You fill the thing with up to 1/2 gallon of fluid, remove your master cylinder reservoir cover and replace it with the Motiv cap attached to it's tank. Then pump it up (kind of like a garden sprayer) and just go to each caliper, attach a clear hose and open the bleeders and drain the old fluid into a container. Start at passenger rear, then driver rear, passenger front and then driver front. The fluid level in your MC stays full automatically. It's about $60 but you'll always have the tool afterwards to work on brakes.
https://www.amazon.com/Motive-Produ...8&qid=1511970287&sr=8-1&keywords=motiv+for+gm

 

[wendal]

Instead of paying somebody to do it, get a Motiv pressure bleeder and you'll be amazed how easy it is. You fill the thing with up to 1/2 gallon of fluid, remove your master cylinder reservoir cover and replace it with the Motiv cap attached to it's tank. Then pump it up (kind of like a garden sprayer) and just go to each caliper, attach a clear hose and open the bleeders and drain the old fluid into a container. Start at passenger rear, then driver rear, passenger front and then driver front. The fluid level in your MC stays full automatically. It's about $60 but you'll always have the tool afterwards to work on brakes.
https://www.amazon.com/Motive-Produ...8&qid=1511970287&sr=8-1&keywords=motiv+for+gm

U da man, sir. Thanks! Bought! Can I use this to install my own braided hoses? IF so, should I just replace the hoses at each wheel before bleeding that wheel?

 

[TigerEyz3]

....Can I use this to install my own braided hoses? IF so, should I just replace the hoses at each wheel before bleeding that wheel?

Yessir! Just make sure that you have a catch pan in place at the junction you're removing. After new hose is in place, make sure that fluid is coming out new hose before connecting to brake caliper... After connecting to brake, make sure fluid is draining out of the brake drain port.

 

[Rocket Man]

U da man, sir. Thanks! Bought! Can I use this to install my own braided hoses? IF so, should I just replace the hoses at each wheel before bleeding that wheel?

It's perfect for replacing those hoses. Replace all the hoses then bleed the system. Just keep an eye on the fluid in the mc while replacing hoses so you don't let it get empty and draw air in.

 

[swat2380]

StopTech hoses have DOT label on them. Don't be nervous about a brake flush or replacing hoses. The fluid does not gush out just a steady drip and as mentioned previously keep your master cylinder reservoir full and you won't have any problems. I haven't driven the Denali yet after replacing everything have a couple other things I am doing.

 

[jrobie79]

from what I've read the proper way to flush it requires a Tech II to cycle the ABS pump, otherwise it'll still have old fluid in it. Is this accurate? If so does anyone have a Tech II? Maybe set up a loaner program, where we put down a deposit to the Tech II owner, and pay a rental fee (and shipping costs), then once returned the user would get the deposit back?

I was thinking about getting a Tech II from alibaba or one of those types of sites, I just don't want to get a bogus piece of equipment and F*** up my truck

 

[sk1dm4rk]

There are threads here and on other boards for other vehicles on the Tech II units. I've not read a post about one messing up the vehicle. Some about the units themselves not working, though. That said, those people wouldn't be in business long if they don't at least get you a working unit. Places like alibaba have dispute resolution through the site, if needed. You may have issues getting any type of support down the road, but you should be able to get a working unit at the beginning.

You can likely get everything you need for under $300. Assuming you already have an old laptop with a serial port that you can use for the programming side, as necessary (doesn't happen very often).

Alternatively, you may want to check into the MDI units. They will support the newer model years that the Tech II doesn't as well as being backwards compatible. I have no experience with those, sorry I can't help further. If I was looking for a unit now, I would at least consider an MDI.

Good luck.

 

[iamdub]

from what I've read the proper way to flush it requires a Tech II to cycle the ABS pump, otherwise it'll still have old fluid in it. Is this accurate? If so does anyone have a Tech II? Maybe set up a loaner program, where we put down a deposit to the Tech II owner, and pay a rental fee (and shipping costs), then once returned the user would get the deposit back?

I was thinking about getting a Tech II from alibaba or one of those types of sites, I just don't want to get a bogus piece of equipment and F*** up my truck

Bleed them as you would normally. Right when you start to press the brake pedal, turn the key to ON (not START) while you continue your pedal stroke. You should be pressing the pedal slowly- about 2-3 seconds form start to stop. Hold the pedal when you get to the bottom, turn the key OFF, pump once more, then do they key ON pump cycle again. Do this 4 or 5 times. When you first turn the key ON, all the systems do a self-check and the ABS solenoids are activated during this self-check. They're not constantly held open like the TechII or MDI would do, but firing them while you're pumping the fluid through the system a few times should be plenty to move the old fluid and any trapped air out of the ABS solenoid block and down the line towards the calipers. I've done this countless times on various makes and models of vehicles I've bled the brakes on and have always had a firm pedal afterwards. NOTE: Lay a 2x4 under the brake pedal to keep the pedal from bottoming out. You can tear the seals in the master cylinder by stroking it beyond it's normal range of travel.

I'm not against owning a TechII or equivalent. But, for a simple brake/bleed job, you can achieve the same results with a piece of 2x4 and a few extra turns of the key.

 

[wendal]

Yessir! Just make sure that you have a catch pan in place at the junction you're removing. After new hose is in place, make sure that fluid is coming out new hose before connecting to brake caliper... After connecting to brake, make sure fluid is draining out of the brake drain port.

Thanks for the additional info!

 

[wendal]

Gentlemen, I want to thank you all for the information. I finally did the work on my truck today, and it was PERFECT. Well, it ended perfect. I did let the Motiv pump run out of fluid once and sent air through the entire driver side rear brake line. but, I filled it up, did it again, and when done, it was perfect. It took me all day, primarily because I decided that if I was going to do all this work, I might as well do brake pads / rotors as well, so I ran up to Summit Racing (Arlington, TX) and bought this kit:
https://www.summitracing.com/parts/pwr-k2068-36/overview/year/2007/make/gmc/model/yukon

When I finally finished, I drove the truck to bed the pads, and not a squeak, not a shudder, nothing. PERFECT!.

 

[wendal]

One question though. The rear hose set has 2 sets of hoses. I only see one rubber hose, the one directly connected to the caliper. Did I miss something, or is the kit (Stoptech) for multiple vehicles?

 

[HiHoeSilver]

One question though. The rear hose set has 2 sets of hoses. I only see one rubber hose, the one directly connected to the caliper. Did I miss something, or is the kit (Stoptech) for multiple vehicles?

The other set is up over the axle in the middle.