Tundra Brake Fluid Change Notes

For most of the Toyota Tundras with the 5.7L Engine you have to use the Toyota Tech Stream Software and the Cable that plugs into the OBD2 Port under dash. Toyota sells the cable for $300, I used a generic $30 cable and it worked fine. Tech Stream has a 2 day use fee of $20 (current price) as of writing this.

The software will basically walk you through the process. It will electronically activate one of the braking system components. This is the reason why you need to use the software. If you don’t you could get air in your brake lines. You also have to be very careful to make sure you do not drain the brake fluid reservoir when bleeding the brakes. The reservoir is very small and this is easy to do. If you drain it, you could again put more air into the brake system. Make sure your brake lines are not leaking. Also I have read from a Toyota Tundra owner that he found part of his emergency braking system was damage, so check that while you have the car safely lifted. From what I read, you can also use this cable and software to properly change the transmission fluid.

if you want to get brake fluid

Click Here: https://www.amsoil.com/shop/by-product/other-products/brake-fluid/?zo=5237175


Finally installed brake booster and master cylinder

Porsche 928 Brake Fluid Reservoir
Cleaned reservoir


I finally installed the brake booster and master cylinder. I had trouble getting the old brake booster off. I actually had to use a Dewalt saw to cut the bolt in the back that connects to the brake pedal. Some mechanics said I needed to count the amount of turns for the nut on the brake pedal so I could put the same amount of turns on the new one. I ended up looking at a manual and everything is actually don’t by measurements. I had to buy an ultrasonic cleaner to clean the reservoir. A new Porsche reservoir for some reason cost over $400. So I just bought a harbor freight cleaner for under $100.


Porsche Power Brake Booster Arrived

928 Brake booster
928 power brake booster

The power brake booster I ordered arrived today. It feels like Christmas every time I get a new car part in the mail. ATE makes the power brake booster for the 1989 Porsche 928 S4. I felt I got a good deal on the price.

     On an enthusiast forum for the 928 Porsche, someone recommended I coat the master cylinder with a clear epoxy to prevent corrosion long term. He also recommend a special lubricant for the rubber portions to prevent it from dry rotting. Before I install this component I am going to order that lubricant and a part called a brake proportioning valve or pressure regulator. My goal is to take care of the components within the engine bag before I start jumping all over the car. I will probably make sure the exhaust system is put back together then move onto the timing. I heard this brake booster is a pain to replace :(.

I will be using AMSOIL brake fluid for my 928. You can purchase it here:


Shipped the Brake Master Cylinder Today

Brake Master Cylinder Rebuild Form
Brake Master Cylinder Rebuild Form

Porsche 928 Master Cylinder Taken Apart
the Porsche 928 S4 Brake Master Cylinder I took Apart

shipping box for porsche 928 brake master cylinder
shipping box for Porsche 928 master cylinder

I previously tried to have a company rebuild my brake master cylinder. They sent it back saying they could not do it. I believe the problem is that it needs to be sleeved.

Today I sent the master cylinder off to another company that sleeves the master cylinder. This company offers a life time warranty. I am a little worried they will send it back because I took the unit part before sending it to them (they specifically asked not to do that) and I forgot how to put it back together. When I took the unit apart, I cracked one of the internal parts. I am assuming a rebuild kit would replace this component. This is the last rebuild attempt. I found another vendor that sells new units a little less than the previous vendors. I believe a rebuilt brake master cylinder is more reliable than the stock one. The company puts a more durable protective coating on the cylinder and the sleeve is more durable than the standard bore. When ever I do get a working brake master cylinder, I also plan on replacing the power booster, pressure adjuster and some vacuum lines. After I am done with the mechanical problems in the engine bay I will get the brakes rebuilt.

Brake Master Cylinder Adventure – caution about vendors


My Project Car is a 1989 Porsche 928 S4. I am currently unable to drive it because the brake master cylinder went bad.

      On a more common vehicle, you are able to go into a parts store and pay less than $100 for a brand-new master cylinder.  Unfortunately, this master cylinder is no longer manufactured. A company called ATE originally build these master cylinders. Due to the lack of supply a new unit cost around $400. I prefer not to pay that high of a price for something I feel is worth less than $100.

     I contacted ATE to see if there was an alternative part number. They informed me there was not. I did find out that there are alternative reservoirs I can use. The reservoir from Porsche cost a couple hundred but a generic reservoir cost less than $50.

     I tried to purchase a very cheap new brake booster pump off of eBay. The vendor had several thousand good reviews. After making the purchase the vendor gave eBay a fake tracking number. When I looked up the tracking number it said a package was delivered to another state. I tried contacting the vendor and his response was very slow. I filled a complaint with eBay but that went nowhere. So, I called my bank and disputed the charge and got my money back. I did some more research on that eBay user and found he ripped of hundreds of people. I was surprised eBay allowed him to continue to sell items.

     I also tried to purchase a rebuilt unit that was priced very cheap on a website. It turns out that some scammer owns multiple fake car parts web sites. After purchasing the fake rebuilt brake master cylinder nothing was shipped for over a week. I tried contacting the vendor and there was no response. So, I called my bank and disputed the transaction and got my money back.

     I then tried sending the old unit to RockAuto so they can have a company called Cardone rebuild the unit. Cardone was not able to rebuild the unit. I believe they could not due to the cylinder needing to be re-sleeved. I found another company that re-sleeves brake master cylinders, I plan on sending it to them shortly.

After I get the brakes working again I plan on using AMSOIL Synthetic Brake Fluid. I use this in my Toyota Tundra and have no problems. This Synthetic Brake Fluid exceeds a lot of the DOT 3/4 standard specifications.

Click here to Purchase AMSOIL Synthetic Brake Fluid