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.