Inliners International Forums General Discussion Hi Performance Installing a brake booster on a non brake booster system

Well the install and brake overhaul are complete with a few final existing problems. We got the brake shaft/rod from a '65 C10 with a stock brake booster. The rod was adjustable so we adjusted it out with about a 1/4 inch left of threads so we didnt want to adjust it out any further. We had to pull the brake pedal close to the floor to be able to put the bolt throught the pedal. The brake pedal is now close to the same hight at the gas pedal maybe slightly higher. I need a longer rod! (Haha i wonder how many guys say that). I need a longer rod but have no clue as to where to get one if the one from a '65 that had a stock brake booster is to short. The booster is mounted the exact same way. If anyone knows what kind of vehicle to get this rod from or where to buy one please let me know. Also the last problem is on the stock system there is a Y connector that splits engine vacuum from the PCV valve and the booster. I went to napa and all the ad was a T connector for the cooling system. Does anyone know if this Y connecter is of much importance or will a T work? If anyone has an answer to either of these questions it would be much appreciated.
Thanks
Jason

Jason, When I changed my front brakes to disc I also changed my master cylinder. I made my rod out of a grade 8 bolt about 8 in. long, cut the head off and rounded the end. As far as the T verses the Y connector I personally don't see why they will not interchange.

T or Y shouldn't matter as long as there are no leaks. Vacuum is going to equalize throughout the hose and fittings. Just be sure to use a check valve at the booster inlet to keep the booster at max vacuum when the throttle is opened. The plastic piece that adapts the vac hose to the booster housing is the check valve on GM units. Resist the urge to replace it with a plain elbow. Under normal driving you might not notice if you didn't use one but if the engine stalls and you want to stop then the purpose of the check valve will become obvious, the brakes will still work but the pedal effort will increase dramatically.

Mike

Jason, what are you putting this booster on? If you are using a booster from a pre 1973 Chev PU, and it has the bracket and linkage that bolts on outside the fire wall, the brake pedal is SUPPOSED to be about gas pedal high. All the cars thru 1964 and trucks thru 1972 used this setup and the brake pedal was only about as high as the gas pedal. The linkage and levers inside the booster bracket doubles the master cylinder travel in relation to the pedal travel. That way the pedal could be lower and still have the same master cylinder travel. After the years mentioned, they did away with the bracket and just bolted the booster flush with the firewall. Thus, the pedal is higher. I guess they did this because it was cheaper?!? I hope this helps. Joe

Knowing what you all know from above. I have adjusted the brake switch all the way out so i can run a low pedal. It cannot go any further and anytime i push the pedal the brake lights dont go off. I have to pull the pedal up slightly and they go off. I had a cop follow me the night i did it luckily i decided to pull up on the pedal a few time si used it and he stopped following me. When i got home i pushed the pedal and the lights were on. So in any event i think i need a higher pedal. NEXT. It seems like it is harder to stop now that the booster is on that when it wasnt on. Any ideas why the booster would make it harder to stop. Do you think the pedal travel has anything to do with it?

Jason, there is a little sheet metal piece that bolts on to the brake pedal that sticks up to reach the brake light switch. You could build something pretty easy. I might have one, but the question is where? Joe

what about the stopping. IT is harder to stop now than when the booster wasnt involved. I would think it would either be better or be the same. Does anyone think it has anything to do with the brake pedal travel? Something just isnt right.

Re:Hard Stopping.Could be the booster was bad when you bought it or it's not getting enough vacuum.18 inches of vacuum is recommended.

but even if the booster was bad wouldnt it just be as hard to stop as it was before? It shouldnt be any harder right? Could it be that there isnt much pedal travel?

Has anyone ever heard of installing a brake booster and it is harder to stop? Shouldnt it just be the same. Could it be pedal travel?

Jason< If the booster is bad or not getting enough vaccuum, it will be like stopping a car with power brakes with the engine off---very hard! Check your vaccuum at the booster. If it is enough, your booster is probably bad. It doesn't have anything to do with pedal travel. Joe

Also,with the engine off, put your foot on the brake pedal with a little pressure.If the booster is good the pedal will go down some when you start the engine. Joe

This has got to be a stupid question. I have done it before but dont own the tool. To check a vacuum advance or a brake booster I need a vacuum gage right? I have seen tools that you jam in the hose and check engine vacuum but what is the tool that is used to check these? Does anyone have a picture or know of one being sold on e-bay...thanks

Jason,Any vacuum gauge will work as long as it reads in the range you are checking. Disconnect the vacuum line from the booster, connect the gauge,run your engine at normal idle and read the gauge. Some engines need the addition of an
auxiliary vacuum pump to achieve the needed vacuum,especially if the engine is cammed up for
horsepower.

Jason are you talking about the hand pump with a gauge that is used to check vaccum advance diaphragms and other vacuum operated controls while they are off or disconnected from the engine? If so then what you want is known as a Mighty Vac and is available from almost any good or not so good auto parts store. There are a couple of different modles. One is plastic and goes around 25 to 30 bucks. The other professional grade is all metal and costs a fair amount more. Both come with a variety of fittings to check out almost anything and the come with a reservoir so you can bleed brakes with them too. You can easily make up your own odd size adapters from items you have around the shop if what comes with the tool isn't what you need.

For most auto hobbyists the less expensive model works just fine. Not long ago Wal Mart used to carry them and they sold them for under $20.

Mike

Jason, I am wondering if you are using a 1/2"(inside diameter)hose to supply the booster. I also noticed you made mention of splittiing the vacumn hose via "T"or"Y"--- I would suggest making the vac. hose to the booster a separate hose that comes from the manifold(large 3/8/npt threaded boss) and run your other vac.lines off the carb.Also do not use "fuel line" hose for this as it is prone to collapse when used as a vac. hose. Large vac hose is available and it may be sold as PCV hose in your area. It has a much thicker wall. Paul

I am using i think 5/16 hose. That is the size of the check valve on the booster. I am at a loss of why the **** booster wont work. All i want is brakes HELP!! I need to go buy the vac gage to see if the booster is even good. Any other ideas

What year vehicle is the booster from? Is the Master Cylinder from the same year? late model Master Cylinders ( namely aluminum)can not be used on early boosters. They will bolt up, but will leak between the booster and master cylinder. Paul

Jason, this a used booster, right? More than likely, it is bad. Even if your vaccuum hose is too small or you are not using full manifold vaccuum, it will build up in your booster and work well at least part of the time-on the first stop or so.Your booster is bad. Joe

Actually is is supposed to be a new booster and a reman master Cylinder. I baught it from Rockauto.com for $100 something dollars I would think it is good i am about to go out right now andcheck to see if it holds vacuum.