Inline Tube - Wheel Cyl. Rebuild

Inline Tube - Wheel Cylinder Rebuild
One of the largest problems with classic car brakes is that your brake fluid is to be changed every few years. Brake fluid collects moisture over time, this moisture has water in it and over long periods of time it creates rust. This means the inside of your components are slowly corroding causing your system to loose effectiveness. This happens with anything that has fluid in it. This includes brake lines, master cylinders, wheel cylinders, and calipers. If your car has been restored in the last few years keep up on the maintenance and change your fluid every 5 years. If your car has never been restored and you are wondering how you can improve the brakes, the first step is changing the fluid. By getting the old fluid out and replacing it with new fluid you eliminate all the moisture which will dramatically increase the effectiveness of the fluid increasing hydraulic pressure by as much as 20 percent. Next you can replace the old metal brake lines which can rust from the outside from being exposed to the elements and can also rust from the inside from trapped moisture. Before rebuilding any component you should consider the cost and labor factor. If the component has never been replaced and it is the correct date coded part for the car it is priceless, if the component has already been replaced with an after market piece, the time in rebuilding may not be worth the cost of a replacement. An original is always worth rebuilding. Most components have only a few rubber seals that need to be replaced and they will be a good as new. Rebuild kits are a small fraction of the component cost but take some labor time to install. If you are working on a driver, seals are quickly replaced in a few minutes, for a show car a more complete rebuild may be desired. All calipers, wheel cylinders, and masters have manufacture markings and date codes specific to that year make and model. Inline Tube replacements have the same shape and function but do not have date codes or manufacture markings. For a concourse restoration these marking add value and detail to the final restoration. By following the steps below you can rebuild you components just like an experienced mechanic. Inline Tube offers all the pieces of the rebuild from the rubber seals to complete caliper ready to bolt onto your classic.

These are the original Delco cylinders and they feature the Delco logo, part number, date code, and wheel cylinder inside diameter of 15/16". The size is important when ordering the seal kit. There are many different size cylinders so if they are not marked you may need to measure the inside diameter with a dial caliper before ordering. If the wheel cylinders are not original they may not be worth spending the time to rebuild. A replacement wheel cylinder cost around $20.00 , the rebuild kit is around $6.00 and your time is worth something.

Drain the Cylinder of as much fluid as possible. In order to get the piston out of the cylinder, leave the bleeder in place and take an air hose at low pressure (25lbs) and insert the end in the brake line hole. When applying pressure make sure your hands are clear of the pistons that is making its way out of the cylinder. When the piston reaches the end of the cylinder wall you will hear a pop of air pressure and the piston will be out. If the dust boot does not come out with the piston pull it out with pliers. Remove all pieces paying attention to the order and direction the pieces are facing, it is easy to forget and improperly install the new parts. In this assembly we will be reusing the pistons, center spring, and cylinder body. The rubber seals will be discarded.

Once the parts are cleaned it is time to phosphate the cylinders. A solution from Palmetto Enterprises is used. On a propane portable stove get a stainless pot big enough for the parts. Follow the mixing instructions for the solution, heat to 175 degrees and drop the clean parts into the solution and once they stop bubbling remove the parts from the pot and spray down with WD-40. The WD-40 heats up and turns to a heavy oil that will soak in and protect the finish. Only use a stainless pot, other materials react with the solution causing pot failure in minutes.

Now that the cylinder is completely taken apart, take a look at the cylinder wall, the wall may have small pits, as long as pits do not run under the inner seals it is ok. The seal is what holds the fluid in so this area must be clean. If there is major rust or heavy pitting where the seals ride this may result in a leaking cylinder even after it has been rebuilt. Light pits located in the center of the cylinder have no affect on performance. This piston will ride against the inner seal. Since brake fluid collects moisture the cylinder usually has a few pits but nothing that will affect the rebuild. If there is heavy pits the cylinder may be unusable and a new one will have to be used. Another option is to have the cylinder sleeved, this can cost $60 to $80 for each cylinder. The cylinder will be bored to the next size and a stainless sleeve will be pressed in.

The assembly will go back together the same as it came apart. First with your finger as a back stop, slide the spring into the hole, then insert the piston seal with the smooth side out and the convex side against the spring, next the piston will go in with the smooth side in and finally the end seal as pictured. Repeat for the other side. When installing the rubber seal and the end seal it is helpful to spray WD-40 or apply brake fluid on the parts to make installation smoother. If you decide to paint the cylinder the brake fluid will eat the paint.

Repeat the same process on the other end of the cylinder.

Once the end seals are in place, use a hammer and a block of wood and lightly tap the seal ring into place. The seal has a metal band formed into the rubber that must seat to the cast body. Once the seal is tapped into place install the bleeder screw, wheel cylinder pins, and you are now ready to install the finished wheel cylinder into the backing plate. The silver and gold zinc parts can be re-plated or Inline tube offers new hardware.

Sources:

Inline Tube - Brake & Fuel Lines, Rebuild Kits, Brake Hardware, Disc Brake Conversions,

15066 Technology Drive
Shelby Twp, MI 48315
586 532 1338

www.Inlinetube.com

Palmetto Enterprises - Grey Phosphate Plating

2311 A Old Parker Road
Greenville, SC 29609
PH (864) 246 3836

Bob’s Boosters - Sliver, Gold, Black Zinc Plating

East Point, MI
PH (586) 774 8883