Wednesday, May 19, 2010

Repairing Pre-1961 and Hawk Master Cylinders

The first thing to do when you get your "new" Stude is to make sure it will stop - as well as go! Because of the age of these classic cars and the inherent wear and tear, it's always a good idea to thoroughly inspect your brake system.

Common brake fluid (such as over the counter DOT 3 fluid) is hygroscopic, which means it absorbs moisture from the air. This also means any car part made from ferrous metal can rust when it comes in contact with the absorbed moisture. This is why you should flush your brake system evey two years. Bleed the brakes on every wheel, topping off the master cylinder with fresh fluid as you bleed. This helps to remove accumulated moisture.

If the brakes have not been bled in awhile, there may already be corrosion built up in the master cylinder. When you pump the brake pedal to bleed the brakes, you can do damage when the internal hydraulic seals pass over the corroded areas. The best way to check this is to take apart the master cylinder and inspect the bore and replace parts where necessary. If there's corrosion in the cylinder, there probably is degradation throughout the brake system.

Some people pressure bleed by forcing fluid through the system without pumping the brake pedal. This is ok for adding fresh fluid, removing air and moisture, but you still won't be certain of the condition of your brake hydraulics.

Up until 1961, the Stude master cylinder was under the floor on the drivers side. From '61 on it was on the firewall, except in Hawks, where the m-cylinder remained under the floor. The cylinder on trucks didn't go to the firewall until '63.

To remove an under floor cylinder, there are two through bolts that attach it to the frame, which may also hold a bracket for the pedal return spring if the car is a standard transmission. Unhook this spring before unbolting the cylinder. On an automatic trannie, this bracket and spring will be absent.

On the back of the cylinder is a large 3/4" hollow bolt that holds a brass distribution block where the brake lines attach. (Note there are two copper gaskets/washers on either side of the distribution block. These will be replaced with new copper washers.) Remove this bolt - then unbolt the cylinder. There's a push rod from the brake pedal to the master cylinder that's attached with a clevis. Before removing the clevis, take note to which hole on the pedal arm the clevis is attached. Remove the clevis cotter pin, slide the shaft out and then as a unit, pull out the master cylinder. Check the clevis pin for wear and replace if needed.

Master Cylinder Disassembly: Pull back the rubber bellow boot. On some cylinder models the push rod is held in place with a snap ring, which will be removed. If there's not a snap ring holder, the push rod/clevis assembly will slide out with the rubber boot from the end of the cylinder. There's usually a build up of corrosion about 1/4" in from the edge of the cylinder bore. You will need to hand sand this with emery cloth before the piston will slide out.

With the new m-cylinder repair kit in hand, compare the depth of the push rod bore between the old and the new piston. They should be the same. If they aren't, you've got the wrong repair kit. Now remove the cap, if possible. Sometimes these are stuck, corroded on and must be broken away. You may get a new cap from your Stude parts vendor. Hopefully the piston will slide out easily. If not, use a metal punch, inserting it through the outlet hole and gently tap the piston assembly apart.

Congratulations - you now have a parts mess! Grin.

Now that everything is disassembled, clean the bare master cylinder with a solvent product, such as Brake Kleen.  Make sure the cleaner is non-pretoleum based, as this will attack the rubber.  Brake Kleen is a chlorine based solvent.  If it comes in contact with open flame or intense heat, it will convert to phosgene gas, which is  poisonous.  You do not ever want to come in skin contact with this gas or inhale it... dangerous stuff.  It was used as a chemical weapon during WWI.  

Inspect the bore of the master cylinder for rust and corrosion. If there are areas of light rust or corrosion with no deep pitting, the cylinder can be honed out. (You may purchase hones from auto parts stores to do this honing.) Reclean after honing. If the cylinder wall pits are deep, rubber parts won't seal and the cylinder must be sleeved or replaced.

Re-assembly: The new check valve seat rubber washer goes in the bore first, then the redisual pressure valve, flat side toward the rubber washer. The piston return spring is inserted next, open spring end first. Then lube the rubber cup piston with new brake fluid. Insert cup end into cylinder with the back flat side facing you. Next insert the aluminum piston with the push rod hole facing the open end. Slide new rubber boot over end of push rod and snap retainer ring into place on the rod, if originally equipped with a push rod retainer. Insert push rod into bore of the piston and install snap ring. Then push lip of boot over the end of the bore.

You are now ready to reinstall the refurbished master cylinder on your car. When hooking up the distribution block, make sure you have replaced (with new), the copper gaskets on either side of the block. Used copper gaskets/washers are compressed, hardened and will not seal properly.

Brake Fluids:  At this point, you may want to investigate the type of brake fluids available for your car. DOT 3 or DOT 4 brake fluids are moisture attracting and if your car sits for long periods of time without running, you can end up with a corroded braking system. DOT 5 is hydrophobic (does not attract moisture). It is a silcone based fluid with an additional advantage of a more stable viscosity index in extreme temperatures.

If you want to convert from DOT3 or DOT4, you must flush and clean your brake line system. Without proper flushing, the mixture of 3 or 4 with DOT 5 will damage the seals and cause brake failure.

DOT 5 brake fluid is not compatible with anti-lock brake systems.

To flush your system, fill your master cylinder with rubbing alchohol and bleed pump the brakes until only alcohol flushes through. Using a turkey baster, suck up the alcohol left in the master cylinder. Take all the brake lines loose at both ends and using filtered, dry compressed air blow out all the alcohol. Keep blowing until lines are thoroughly dry. Carefully, gently blow out the master cylinder until completely dry.

Re-attach the brakes lines, fill the rebuilt master cylinder with DOT 5 and pump bleed the lines until all air is pumped out and brake pedal is solidly stopping.

Sunday, January 31, 2010

Steering Geometry

There is a resto-mod trend to change out worn Studebaker stock steering gear boxes with modern rack and pinion set-ups. There are design challenges in doing this correctly.

The new rack has to be mounted safely and solidly to the car frame. The steering column shaft has to clear the engine, exhaust, etc... during engine operation. Even the smallest amount of rub or bind will compromise your steering control and safety. Well engineered, sturdy parts are important. In other words, don't go cheap with your replacement parts in this area. Safety is paramount.

Studebakers have a rear steer system. The majority of new cars have front steer. The new steering set-up you install also has to be a rear steer so when you turn the car steering wheel left, your car won't go right.

Case in point. A person I know, who doesn't understand steering geometrics and who shall remain nameless, installed the wrong set-up in a custom '58 El Camino. He backed the finished car out of the garage, turned the steering wheel right...the car turned left and he backed right into a power pole. It took me a day and half to repair his damage and a week to stop shaking my head in disbelief.

This Studebaker steering assembly diagram, from the perspective of the driver's side front of car shows a stock set-up. Ideally you want the pivot of the tie-rod (which attaches to the end of part #1202-34) to be in the same plane (height and width) as the control arm inner pivots (which bolts to assembly parts #1204-85, #1024-86, #1204-91, #1204-93).

By keeping the pivots in the same plane and in close proximity to each other, their working radius of arcs are more closely matched. When these fulcrum points are not closely matched and the vehicle tires hit a road bump, you will experience bump steer. This is when the car motion suddenly grabs and darts without any steering wheel input from the driver. This bump steer phenomenon will be mild to extreme depending on the placement of the steering pivot (fulcrum) points and can be very dangerous.

It's advisable to have a custom steering rack made that has both pivot points placed in the same plane as the lower control arm inner pivot points (rubber bushings).

There's presently a company that's producing custom width Dodge Omni steering racks that can be modified further to fit the Stude. Another option is to modify Chevy Corsica or Pontiac Grand Am firewall mounted center steering racks. To modify these racks, mount them on the stock cross member at the same plane, using stock Studebaker tie-rods. These type of mods will give you a more precise road feel, however you won't gain any geometry advantages over the original stock Studie design.

Sunday, October 4, 2009

Rebuilt and Ready To Go

Putting this power steering control valve on my '63 Avanti with the rest of the power set-up. Looking forward to one hand turning, again.

Sunday, August 23, 2009

New Gas/Old Rubber - Ethanol Problems Part 1

The ethanol alcohol additive in the gas you're pumping into your car is attacking your engine. Especially if you're using this gas blend to power your Studebaker or classic car and haven't upgraded the rubber inclusive parts and hoses.

With the implementation of the EPA Renewable Fuel Standard Program, ethanol fuel is now widely sold in all 50 states. Presently, each state government independently determines ethanol labeling requirements at public gas pumps. This labeling varies from state to state. Some states do not require posted labels on gas pumps, so you may not know if you're pumping an ethanol fuel blend into your vehicle. For more information per state ethanol labeling, check this website.

Alcohol is an outstanding A-1 solvent! It will dissolve plastic, rubber, some types of fiberglass and can pit aluminum. It will soften and stretch rubber, eventually drying and cracking the alcohol induced brittle rubber. Ethanol will dissolve your rubber part fittings, seals and hoses, creating sludge that invades your engine. This coating of sludge on the interior of your engine can cause it to bog and run ragged. The sludge can also damage pistons. Worst case scenario: if you continue to replace rubber parts with rubber, the sludge build-up over time can cause the engine to seize.

I worked recently on a 1967 Avanti where the 'original to the car' fuel pump diaphragm had ruptured. Because the gas tank in this Avanti sits higher than the fuel pump, the gas flowed through the rupture into the engine, then drained down filling the crankcase with gasoline. I replaced the old fuel pump with an ethanol gas compatible pump to prevent future crankcase oil dilution and possible engine seize. The best way to protect your cars engine performance from ethanol alcohol attack is to upgrade your rubber parts.

Rubber parts and hoses that should be replaced with fuel injection grade products:

...Accelerator pump in carburetor
...Diaphragm and valves in older fuel pumps
...All flexible hoses that deliver fuel or carry fuel vapor
...PVC valve hoses that run between carb or manifold and the engine
...Power brake hose which runs to intake manifold, which carries fuel vapor
...Best to use new carb rebuild kits as older kits have rubber tipped needles
...Check the fuel filler hose where you pump the gas into the car

A good choice for rubber replacement are synthetic rubber-like products made from the new elastomers. Dupont is producing automotive application products under the trade name of Viton. This product offers not only heat resistance (400°F/200°C), but is also resistant to aggressive fuels and chemicals. It has been tested with up to 15% alcohol solutions with no loss of physical integrity. Look for the Genuine Viton seal and ISO 9000 registration code on your replacement rubber parts.

If your car is not a daily driver and you're storing it for a long periods of time, the best course of action is to add a gas anti-oxidation, anti-degradation product, such as Sta-bil to the fuel. I don't recommend draining the gas from your car. It's almost impossible to completely drain and remove residual gas from a fuel system. Gas draining will also expose bare metal parts to moisture and air, which can cause rust and corrosion.

Non-ethanol alcohol gas has a fairly long shelf life, however ethanol gas is good for only about 90 days before the inherent water begins to separate out. Because this can lead to engine corrosion, it's a good idea to replace the ethanol gas with a fresh tank of gas at least every 3 months. Drive the car, bringing the fuel gauge down to almost empty before you gas up again. This also adds the beneficial effect of running other fluids through your drive system which aides in keeping parts and hoses lubricated and protected.

**NOTE. This article is written to address ethanol alcohol issues in older car engines. Since the inception of the EPA Renewable Fuel Standard Program, new car engines are being designed to withstand ethanol alcohol problems.

Friday, August 14, 2009

Looks Like a Honk'n BIG Piece of Jewelry

Clean and Shiny - good to go.........

Carter AFB 3506 - original to my '63 Avanti

Photo Credits - GBZ

Saturday, July 18, 2009

Funny of the Day

A guy pulls into his mechanic's shop in his Studebaker pickup with 'Ole Blue' his dog in the back. The dog doesn't move the whole time the mechanic works on the truck. Mechanic sez "That's got to be the laziest dog I've ever seen".

Studie owner says "Yup, he sure is. He used to be hard work'n hound, but I don't know how to get him goin' again."

Mechanic sez "I can fix that." He reaches into his toolbox and gets an eyedropper. He goes to a gas can, pulls up gas in the eyedropper and puts a drop of gas on the dog's tongue. The dog jumps up...runs around wildly.

The owner says "Wow, that sure did the trick." Suddenly, the dog stops and keels over. The owner yells "OMG, is he dead?"

The mechanic says "Nah, he's just out of gas."

Stromburg Two Barrel Question & Answer

Question: I recently rebuilt a Stromburg-WW series two barrel on my '63 Lark. It's still not running right, it bogs on acceleration and floods out. I need help. What do you suggest?

Answer: The spring that holds the float pivot may have inadvertently been left out when the carb was re-assembled. Check to be sure this horse shoe shape spring is present on top of the float pivot under the fuel bowl cover (or air horn, which is another name for this part).

Place a new inline fuel filter in the fuel hose before the fuel pump. The smallest speck of dirt in the gas may cause the float valve to not seat which can then cause flooding issues. Also make sure the float is not damaged or sinking. Refer to my previous post regarding how to check your floats for leaks - Click Here .

Bogging problems may be caused by the accelerator pump circuit. There are two check balls; one is in the fuel bowl. This is the inlet to the pump intake. There's a hollow brass screw in the bottom of the fuel bowl next to the accelerator pump. The larger ball goes under the brass screw. The smaller ball goes under the discharge nozzle. Both balls must be present and placed correctly or the carb will lean out (or bog) when you quickly accelerate.

Check your timing with a timing light. If the timing is correct as per your shop manual, then check the distributor vacuum advance. Pull the distributor cap. You are going to place a length of vacuum hose on the vacuum advance canister nipple. But before doing this, make sure the nipple is leak free by squirting soapy water on it and blowing into it to check for bubbling.
**It's important to not get the interior of the distributor wet while doing this. Place the hose on the nipple and suck on the other end of the hose to check the movement of the ignition breaker plate. The plate should move towards the canister. Plug the end of the hose with your tongue. The vacuum advance canister should maintain vacuum. It should not leak down nor the breaker plate rotate back to the initial non-vacuum position.

Some canisters are quite stiff. Rather than sucking on the hose, you may need a good manual vacuum pump to check for vacuum.

If the vacuum does not maintain, then replace the vacuum advance unit. If the breaker plate does not move it may need to be cleaned. Do this by disconnecting the vacuum advance link (do not lose the nylon retaining washer - they usually go flying when you pry them off). Spray the pivot area near the point cam with penetrating oil and move the breaker plate back and forth to free up the action. If it doesn't move smoothly, then it's time to rebuild the distributor.

Also make sure the vacuum advance hose is hooked to the front vacuum port on the carburetor. Check this hose to make sure it's in good shape with no holes or splits to cause air leakage.