• To ALL forum users - As of late I have been getting quite a few private messages with questions about build ups here on the forum, or tech questions about your personal project. While I appreciate the interest, sending me a private message about these topics distracts from, and undermines the purpose of having a forum here. During the day I wear many hats as a small business owner-operator and I work tirelessly to provide the absolute best service possible to you, our valued customer. When I created this forum I rounded up some of the best minds I knew so that any tech question you might have could be asked and answered by either myself or one of my highly experienced moderators, this way the next time this same question is asked the answer can be easily found and utilized by the next IH enthusiast having the same question. This allows me the freedom to run the day to day operations of the business and minimize the impact to shipments and shop activities that these distractions can cause. It is of the up most importance for me to complete the daily tasks in order to best take care of you our customer, all the while providing you a forum to get the level advice and input you have come to expect and deserve from the premier IH shop in the country.

    So with that I ask that anyone with a question about one of our build ups or a general tech question to please use the forum as it was intended. I am absolutely available by telephone to answer your questions as well but at times may direct you back to our website to better field your question or questions. Most other private messages I will be glad to answer for you.

    Thank you for your understanding.

    Jeff Ismail

how to determine if its the Master cylinder or the proportioning valve.......78 traveler


New member
The brake pedal went to the floor the other day and lost brake pedal pressure. Came home and went through the rear brakes and front brakes looking for leaks, looked near the booster and master cylinder, proportioning valve and the front splitter to the front disc brakes. NO brake fluid leaking anywhere and the master cylinder reservoir is full still. The front brake lines (both are cleared), the lines are cleared and all bolts with ports are cleared.
So...... Master cylinder or proportioning valve, how do i determine which is the culprit without buying both? I have tried to bleed the brakes and the brake pedal still wont hold pressure.

any ideas?


Master cylinders go bad. Valves not so often. I recommend against replacement with a remanufactured unit. Pony up for a truly new MC.