UNSTICKING FERRET BRAKES or FREE AT LAST!BY VINCE BLOOM |
| Locked brakes seem to be a common problem on Ferrets since five
of the nine that I have worked with had locked brakes. I have seen them
completely locked to the point that vehicle would only move when given a
lot of throttle to ones that merely had too much drag in them. If your
Ferret pulls to one side when you are driving or when you apply the
brakes, I suggest you check to see if you have a locked or dragging
brake.
A few notes before I get started. I am going to assume that you have some basic knowledge of drum brakes and auto mechanics; if you don't then you should seek assistance from someone who does. I don't know the proper designation for some of the components, so I will call them what I want - call it mechanic's privilege. These are my experiences from the few that I have worked on. I make no guarantees that your vehicle is put together the same way. There may be some modification - field, official, or otherwise, on yours that is not described here. Also, and most importantly, take notes of where things came from when you took them apart so you know how to put them back together. These instructions should help quite a bit, but I may have missed a small bit here or there. With that said, here's the plan. |
| DIAGNOSING THE PROBLEM |
| First, you need to determine if there is a locked brake and which wheel it is. To do this, raise both wheels on the same side of the vehicle. (You can get away with just doing one, but two is better.) Make sure that the hand brake is off and the transmission is in neutral. Each wheel should rotate freely for a few inches until it takes up the play in the bevel box. Once the play is taken up, the other wheel on the same side should turn with it. If you have only raised one wheel, you will only be able to move the wheel until the slack is out of it. You should check all four wheels, if you find one that's locked, it's possible that there's another one locked also. |
| EQUIPMENT |
| One person can do most of this job, but you'll probably need help bleeding the brake lines. You will need a means of raising both wheels on one side. I do this with 6-ton bottle jacks. You can use a smaller jack, since each wheel on a Ferret should support no more than 1-� tons. I tried lifting one wheel with one of those cheap "2-ton" floor jacks. It started to lift it, but didn't seem to like it too much. I prefer the bottle jacks; they take up less floor space, they don't have wheels so they can't roll around when you lift the other wheel, and they're cheap enough that there's no reason you shouldn't have at least two. If you are doing a front wheel, you may want to raise the other front wheel so you can turn the steering wheel easily. You will also need the usual assortment of wrenches and sockets, a lug wrench, a large flat head screwdriver, penetrating oil (such as PB Blaster or QS14), anti-seize compound, cleaner/degreaser, brake fluid, grease (all purpose), and plenty of patience. Also, get a 1-1/8" rubber wheel cylinder cup for each wheel that needs done. Most good auto parts stores will sell these individually. If not, you may need to buy a rebuild kit that has that size cups. I would avoid the chain discount stores, as it's been my experience that if they can't look it up by the year, make, model, color, number of doors, etc on their computer they are of no help to you. |
| GETTING TO THE PROBLEM |
| Safety first - chock the wheels, use jack stands, etc. First, you
need to remove the wheel. DO NOT REMOVE THE OUTER NUTS ON THE WHEEL.
These nuts hold the wheel together. They should be painted red, and with
good reason. If you remove them while the tire is pressurized you can do
great harm and possibly kill yourself - read the sidebar about combat
rims below. Only remove the eight lug nuts. If there are more than
eight, you are removing the wrong nuts. Remember that the left side of
the vehicle normally has left-handed threads. There should be an "L"
stamped on the lug if it is. Be careful taking the wheel off as it is
very heavy.
 Next, you to loosen the adjustment bolt on the backing plate of the brake. This is on the opposite side as the wheel cylinder and looks like a hex nut on top of a square nut. Using a 3/4" wrench turn the square nut counter-clockwise. While you are turning the square nut, make sure that the hex nut is turning with it; you want both of them to loosen the same amount. Loosening the adjuster should allow the brake pads to come together and unlock the brake drum allowing it to turn. Now you are ready to remove the brake drum. On the face of the drum you will see two slotted screws.
 Remove them. This may require some penetrating oil and patience. Be careful, the slots aren't deep and strip out easily. If you loosened the adjustment enough, the brake drum should slip right off. If not, use the two slotted screws in the threaded holes that are 90� away from where they were. As you turn these in, it will push the brake drum off the hub. Now you should have a good view of the tappet and actuator. If you remove the brake shoes, make sure that you note which way they were so they can be put back the same way. |
| THE WHEEL CYLINDER |
| Start by removing the brake line where it connects to the hull.
This side has a swivel connector on it. Then remove the line from the
wheel cylinder. Have a drip pan handy since this line is full of brake
fluid. Remove the bracket on top of the backing plate that holds the
hand brake cable. Remove the two bolts on the rear of the cylinder. If
this is on a front wheel, you may need to turn the steering wheel to get
enough clearance to pull the bolts out completely. Pull the wheel
cylinder off the backing plate. There are three "fingers" that stick out
of the cylinder that actuate tappets to move the brake shoes.
On the side of those fingers is a pin, about �" in diameter. Tap this pin out and remove the center finger.
 This whole finger assembly will probably be covered with grease. Remove the four bolts from the top of the wheel cylinder. The other two fingers are held on by C clips, which are back inside the assembly. Remove the C clips by driving them off. Lift the top off the assembly and remove the clips entirely. There is a cotter pin that may need to be removed also. Removing these fingers is tricky. You need to rotate them as much as you can to get enough clearance to slide them off the pins. DON'T FORCE ANYTHING. If you break one of these, you won't be able to pick up another one at the local parts store. Once the fingers are off, the handbrake piston can be pulled out the top.
 The other piston will remain in the bottom of the unit. To remove this, you can blow compressed air into the fitting where the hose went. You may need to spray some penetrating oil in there and let is soak for a while, after all this is what is locked up. You can try tapping the piston back down to break it free before blowing it out. When you tap it down, brake fluid will probably shoot out of the hose fitting, so be careful where it's pointing. If using compressed air, the piston will shoot out with some force. When you do this, have a rag over the openings to catch the parts when break loose. Under the piston are a rubber cup, a plastic expander and a spring.
 Clean everything thoroughly. The spring and the expander can be reused as long as they are not damaged, but you should replace the cup since they are commonly available and inexpensive (about $2.50 apiece at a local shop.) If you need to replace the spring or the expander, you should be able to find a wheel cylinder rebuild kit with similar parts. Now that everything is disassembled, give it all a good cleaning. I use a Dremel tool with a brass brush to clean the bore of the cylinder. Since the cylinder is aluminum, there shouldn't be any rust or corrosion inside, just dirt. You could use a cylinder hone to clean this out, but be very careful not to get too aggressive with it. Give both pistons a good cleaning also. Remember, the foreign matter in there is probably what caused the brake to lock up in the first place. |
| THE TAPPETS |
| You want to make sure that the tappets are free also. These are the pieces that the fingers push on to expand the brake shoes. To do this, pull up on the brake shoe holders and see if they move freely. If not, lubricate thoroughly. And work them back and forth. I don't know of an easy way to remove this unit, so I work with them in place. |
| PUTTING IT BACK TOGETHER |
| For the most part, it's the reverse of taking it apart. Reinstall
the spring, expander, cup and piston into the cylinder. Insert the
handbrake cylinder and reinstall the fingers. When you put the c clips
back on, you may need to squeeze them shut with a pair of needle nose
pliers. I put a small bead of form-a-gasket where the handbrake assembly
meets the cylinder to seal out any dirt. There is a gasket on the
backing plate where the cylinder attaches. I removed this and used
form-a-gasket there also.
 I also gave all of the internal components a good coating of grease to keep them lubricated. To re-install the cylinder, you may need to expand the tappets by prying one of the brake shoes up.
 This should allow the wheel cylinder to go in easier. Attach the brake line and fill the cylinder and the line with fluid. Open the bleeder a bit to let the air out. Filling the line and the cylinder now will save time bleeding the brakes later. While you still have the wheel off, this is a good time to check the bevel box fluids and grease all of the suspension components. After everything is back together, bleed the brakes like a normal car, start with the left rear, right rear, front left, front right. |
| OUNCE OF PREVENTION |
| Now that your brakes are free, try to keep them that way. I only use my handbrake when necessary - during starting or when parked on an incline or in public. I never leave the handbrake on when I park my Ferret in the garage. As you can see from photo of my garage, sometimes things get piled up behind the Ferret and it doesn't get out for a few weeks. |
| WORDS OF CAUTION ABOUT MULTIPLE PIECE RIMS |
| A few years back a friend and I bought a 1943 Dodge WC-63 6X6. As
with most WWII Dodges, it had combat rims that bolted together. Since it
had been probably 20 years or more since they were last apart, we had no
luck separating them by hand. We came up with the genius idea that if
you weren't supposed to unbolt the rim with the tire inflated as it
could blow apart, then that must be a good way to dismantle them. With
all of the nuts removed, we lashed a chain around the rim and the tire,
and proceeded to inflate it. When the pressure got high enough, the tire
definitely came apart. On the first attempt, it came apart with such
force that the chain bent the outer rim. On subsequent attempts, we
started a few nuts onto the lugs to hold them in place. We also tied a
string to filler valve so we could find it when it blew off the air
line. When we were doing this, we had the tires laying flat on the
ground. The most violent one bounced the tire at least 5 feet off the
ground. It takes a lot of power to lift a 9.00 X 16 tire and rim that
high, that fast! That showed me just how dangerous these types of rims
could be if handled improperly.
My father told me about changing a tire on a split rim. The wheel was off a deuce, probably 9.00 X 20 or and 11.00 X 20. He said the tire was laying flat on the ground and he was standing on top of it while inflating it. The split rim wasn't seated properly and blew apart. The force lifted him and the tire off the ground. Accidents like these are the reason most tire shops in the US won't work on two piece rims of any type. |
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