Review on 🔥 Dorman M390259: High-Performance New Brake Master Cylinder for Superior Braking by John Kachinosky

There is never a good time to reset a master cylinder. However, mine broke down in the driveway just minutes after my wife and I had driven about 40 miles on one charge. Pretty lucky, right?! Imagine an old red farm truck with ZERO brakes in the Kentucky hills with a full load of firewood. Might be clumsy. Anyway, I got distracted enough and regressed and became obsessed. I did my homework and discovered that my truck had two master cylinders, one standard and one heavy duty. With the Cowboy H3LL, I didn't want to pay full retail price for an OEM part. So I double and triple checked that this Dorman part number fits my Big Red Beast before ordering it. This part was way cheaper than anything I could get locally and with prime shipping I only had to wait 2 or 3 days. While waiting for the part to be delivered, I watched many videos on replacing the master cylinder and bleeding the master cylinder! Bleeding a new master cylinder is a must! Otherwise you will force air into all the brake lines. For that, I recommend Dorman Companion Part 13911 Master Cylinder Bleed Kit for about $8-$11. I got one locally when I bought my brake fluid. I was able to bleed my MC right on the truck before connecting the fluid lines. I also bled the ABS head unit before bleeding the individual brake lines. It's very easy for GM trucks if you have two people and a beer. Installing the MC was pretty easy. Should be an easy 1-2 hour job if you're mechanically inclined, you have the right tools, help and enough beer. One pitfall that can happen with a new MC is that you might find a brake fluid leak that you didn't even notice. In fact, I think the strength of the fresh MC eliminates the weak points in the old lines. It happened to me of course! I had to hire a specific driver to take me to the parts store to get a 6ft metal brake line that I had to bend and curse to get under. 3 hours later the MC was installed/bled, the ABS head unit bled, the brake line renewed and all individual brake lines bled. The truck hasn't stopped this well since 1998 AD. I hope this helped you or at least entertained you! Good luck on your driving (maybe alcohol) adventures!