The Stovebolt Site Forums The Shop Area General Truck Talk Brakes EXTRA -SUPER sensitve

My brakes are acting funny. I don't know anything about brakes, but I've heard that they could have "swollen up" causing them to be EXTRA sensitive. So, to look at this, do I need to pull off the rear tires and drums? Then what? Look at the cylinder? Look at the shoes? I don't know where to start. It could even be the front. I have no idea.

Please help.

You didn't say much about the symptoms of your problem, but if by "extra sensitive" you mean the rear brakes lock up very easily, I had the same problem on a toyota pickup. In my case, the differential had been overfilled with gear oil, which made its way through the axle tube into the brake drum. For whatever reason, that oil made the brakes so grabby it was an unbelieveable hazard. All I had to do was change the brake pads and check to make sure the oil was at the appropriate level and that solved it.

Oh yea...
Here's what it is.
about 80% of the time it will do this, not all the time though. I'll go to push the brakes and BARELY touch them, BANG! they come to a screeching halt. I may be exagerating a little, but not a whole lot. It's very dangerous. I'll check what you said. Thanks

Definitely check for oil or brake fluid leaks. I would also adjust the brakes. I've had some trucks that the brakes would grab when the brake adjustment started getting a little loose.

Okay, I went outside and checked it out some more.
It's defenitely coming from the rear brakes and it feels like the right (passenger's) side. I don't know how to remove the drum though

Since these brakes haven't been replaced in probably 20 years, should I just take it up to Midas and have them do there $99 brake change?

And last, I did the "self adjusting" way of backing up and hitting the brakes. That didn't seem to phase them. They still lock up when they're touched.

:mad: :confused:

Thanks guys.

-Stephen

From what I understand, the self adjusting system only tightens the brakes, to compensate for wear. if the brakes are too tight, you have to loosen them by hand. The drums should just slide off the hub. Normally the wheel holds the drum on. Some trucks, like my 3/4 AD, have large flat-head screws holdin the drums in place. Check between the lugs. There would be 2, not quit opposite each other.

Way back they put tin lock washers of sorts over the lug nuts to keep the rear drums from falling off when the wheel was taken off. Most cars/trucks don't have them on anymore. Loosen the adjuster and then the drum should come off fairly easily. A lot of times when vehicles are in storage the brakes get dirty and when driven again occasionally get surface rust on the shoe from the drum. It can be sanded off. As far as grease or differential lube on the shoes, my experience is the opposite. My brakes did not work effectively and when I pulled the hubs there was fluid in them and on the shoes. It was obvious my seals were leaking and after cleaning the entire brake assembly with brake cleaner and scuffing my shoes I checked further and found the breather on my rear axle was stuck closed. Cleaning it and freeing it made the difference. So far no sign of any leaks.

The brakes in my 46 were new when i bought the truck....new in 1980 that is...grease etc got into the shoes. The shoes would grab, lock up and not release. A new set fixed the problem right away. Even if the shoes look good, does not mean they are.

If we are talking/writing about your 64, I would re-do the brakes....lines, wheel cylinders, shoes, master...the whole works...if you have not done so already. As far as taking them to Midas...buy the shop manual and try it yourself. It is not hard to do. Lines rust from the inside out..they look great on the outside until you do an emergency stop...the line ruptures and you hit was you were aimin at. .a shop will nail ya on a line job. Buy a bender, save the old lines when you take them off. Take this opportunity to upgrade everything you want on your brakes...like the master cylinder, or discs up front or whatever you want..but do the brakes...you will save yourself a major headache.

Sticking emergency brake cables can cause rear brakes to grab also.

99 bucks???? good luck on that one hardy

I agree with the posts that feel the rear diff lube is the culpret. Also, you can't adjust your brakes by backing up and stomping on the brake. The only thing that "self" adjusts the brakes is using you parking brake. All of the adjusting mechanism are connected to the parking brake system. Pull the drum in question and clear all of the hard parts and replace the shoes and fix the source of the leak. I wouldn't try cleaning the shoes, they soak up petroleum all the way through. Good luck,
Scott

LOL Hardy, hearing your description of the problem brought back some vivid memories of screeching halts in rush-hour traffic. About taking the drums off, they usually take some rubber mallet motivation, just keep tapping around until they loosen up and come off. One thing '48 reminded me of when he said, "don't try to clean the shoes" is that you absolutely have to clean every single thing inside the drum. DO NOT SPARE THE BRAKE CLEANER!!! I used up about a can and a half when I went into that toy-truck. Nothing would be more aggravating than fixing the problem only to have the old crap heat up, seep into the pads, and make the problem come back.

if the drum won't come off you may need to hit it firmly with a hammer ..carefiull not on the edges!!next to the studs but not on the studs .
this will unlock the friction that has developed, i've beaton on drums for a while before they broke loose. just keep a firm grip and turn the drum steadily and she'ell give.

Alrighty guys,

I went out and started from the top and worked my way down. Followed all the lines and everything. Not a drop. No leaks, nothing.

So now I'm feeling it's the shoes causing the trouble. I've got somebody looking at it Monday, so I'll let ya'll know how it turns out. Thanks!

-Stephen

Don't breathe the brake dust.

Hey Guys!
GREAT NEWS!
My shoes are practically gone, my wheel cylinder is leaking, and my brakes are still messed up!
I was going to put some pictures on here of it, but decided not to after I found out the problem. From the right side of the cylinder, where the rod enters it, it is leaking. The shoes, instead of being about a 1/4" thick, are about the width of a nickel or less.
Why am I not upset? Let me tell you:
1) I finally got the drum off haha
2) I checked with Midas and finally understood why Fred was laughing at me.
New Shoes - 89.99
New wheel cylinders - about 70.00
Drums rotated - I don't know but a lot
Well, I was talking to my friend up at O'Reilly who said he'll do it all for 50.00 if I buy the parts. The parts cost 35.00 for everything. That brings a total of $85.00 saving me hundreds!

I sound like a commercial, but I'm happy!

I also rebuilt much of the dizzy and it all turned out good. The truck has a LOT more power now. I didn't think it would be that noticeable, but it feels good!

Thanks guys!

If all the above doesn't fix your problem a defective power brake booster can cause "super - sensitive" brakes.