Brake problem on a 79 Accord HB

[4791InitialPrelude]

Hello all:

As the title indicates, the brake is problematic on my 79 Accord hb; it pulls to the right when braking and the pedal pressure is soft and can be depressed all the way to the floor w/ little effort. I've not yet spent the time to investigate yet hoping that one of you will point to me in the right direction with what to start from. As this isn't my daily driver, it's only driven when necessary and only in short distances.

Please let me know your thoughts and suggestions.

Thank you in advance and have a blessed day.

CH

[2ndGenGuy]

I'm going to guess that you've got air in one of your lines, you have a seized caliper, or one of your master cylinder circuits has failed. The pedal going to the floor makes me think you have air in one of the lines. How is your brake fluid level? Could also be a stuck caliper as the sliders on the front brakes are not supposed to be lubed, and tend to get sort of stuck as time goes on.

First thing I would do is bleed out your brakes. It's free, and may just solve your problem. While you're bleeding, you can check the calipers for action and make sure they are both working and not sticking. Check your lines for leaks, as on an old car like that, rot is a definite possibility.

You also will need to adjust your rear brakes to get completely rid of the softness. They are not auto adjusting like newer cars. The adjusters, if they were like mine, where they were never used, will probably be seized up, but if you can turn the square bolts on the back of the drums, you will be golden. Key is to turn them clockwise until the rear wheels drag heavily when you spin them, then back them off two turns.

[4791InitialPrelude]

2ndGenGuy:

Thank you for the sound advice and I apologize for not extending the thanks earlier. The weather here has turned cold & wet for the time being and haven't had the urge to check just yet as the 79 Accord isn't my daily driver (but soon will be). I will keep you updated, of course. Your knowledgeable advice is always appreciated.

Thank you again.

[QUOTE=2ndGenGuy;983592]

[2ndGenGuy]

It's all good. Just keep us posted! Keep your 1gee high and dry for the winter and keep us updated when you get her back on the road! :)

[4791InitialPrelude]

2ndGenGuy:
The weather hasn't gotten any warmer but I am determined to find a cure for the soft pedals and slow brakes. hehe I want to let know that I've checked the brake fluid level with generic DOT3 brake fluid (found at WalMart) and it's full as ever. I'll check to see again whether it's leaking at all. As a determined diy'er and having a second vehicle to back up, how would I go about to bleeding out the brakes? Any tips upfront that you'd recommend specifically for the 1st Gen Accord?

Thanks in advance.

[Ichiban]

2ndGenGuy:
The weather hasn't gotten any warmer but I am determined to find a cure for the soft pedals and slow brakes. hehe I want to let know that I've checked the brake fluid level with generic DOT3 brake fluid (found at WalMart) and it's full as ever. I'll check to see again whether it's leaking at all. As a determined diy'er and having a second vehicle to back up, how would I go about to bleeding out the brakes? Any tips upfront that you'd recommend specifically for the 1st Gen Accord?

Thanks in advance.

Well, I'm almost 2ndgenguy...

Start by getting a flare nut wrench. 10mm is the size you need. Then get a buddy, and some beer;

Have your buddy SMOOTHLY begin pumping the pedal, and once it builds resistance, hold steady pressure. After stuffing a rag under the master cylinder, crack one of the lines with said flare nut wrench. If bubbles come out, close the flare again, and ask buddy to release the pedal. You want to make sure the flare is closed before buddy releases the pedal or air will be drawn INTO the system. Oops. Repeat using the pedal to force out air from that fitting until no more air escapes, just clear fluid. You may hear air bubbles "popping".

Remember:

Pedal down

Crack fitting, watch for fluid

Close fitting as soon as fluid stops

Then release pedal

Repeat until just fluid comes out.

Repeat for the other line coming from the master cylinder.

Move now to the proportioning valve. Not sure if yours has bleeder screws on it or not, or if they are seized. Using either the bleeder screws, or the lines coming from the master cylinder, repeat the process again. Pump, hold, crack fitting/bleeder, tighten, release.

Check pedal pressure after each "fluid venting" If a bunch of bubbles are accompanied by a sudden improvement in pedal pressure, there's your problem.

Always keep a good eye on the master cylinder fluid level, if it goes dry, you will have more air in the system than you can comprehend.

Carry out the same bleeding procedure now at the wheel cylinders. Begin with the cylinder furthest from the master cylinder, ie rear passenger. Because Honda had this funny idea to diagonally oppose their brake circuits, defy conventional logic by bleeding the front drivers next. It is in fact the next cylinder on the same circuit. Then rear drivers, lastly front passengers.

Some diagnostic tips:

(assuming you don't have cracked drums or other major foundation brake brokenness)

-If a soft pedal can be "cured" momentarily by pumping the pedal, the problem is either air in the lines, or excessive space between pads/drums. Bleed brakes and/or adjust brake clearances.

-If a soft pedal remains after pumping the pedal vigorously;

Fluid on the ground: repair the fluid leak
No fluid on the ground: suspect master cylinder failure. Check fluid levels.

-If pedal creeps towards the floor under constant pressure; suspect master cylinder failure, leaking wheel cylinder.


Hope some of this helps.

[Ichiban]

Read this too, I had to describe brake systems to stupid people, but still some good info:
http://www.3geez.com/forum/showpost.php?p=860394&postcount=25

[4791InitialPrelude]

Ichiban:

Whoya calling stupid? hehe...

I think you've just diagnosed my problem with the explanation; the brake pedal will firm up on the pressure after several pumps, so seems as if there are air in the lines. I'll let you know what's up with photos before I do anything (stupid). hehe

Just forewarning ya: there are going to be many more stupid questions from me because I am very new to the diy scene with cars in general and will need many more intelligent AND lengthy answers/solutions. If y'all don't mind the time to share your knowledge, that is. I'll keep you posted.

Thank you very much for taking the time to help with my 1st Gen issues.

[Klavier]

Could also be a stuck caliper as the sliders on the front brakes are not supposed to be lubed, and tend to get sort of stuck as time goes on.

NOT supposed to be lubed? When I did the front pads on my girl's car this weekend, I lubed the sliders as they were dry and sticky. Cleaned, then greased with some anti-seize so they would, well, slide. I also bled her brakes, apparently in backwards order. The pedal is now slightly more squishy than it was when we bought the car, so I am going to bleed the brakes again this weekend in correct order and see if that fixes the problem, but should I also remove the calipers and get all the grease off of them? Could this be contributing to the brakes being a little more soft than they were?

I will also be replacing the drum brake shoes this weekend, I will try adjusting the drums as you said if nothing else works.

[2ndGenGuy]

Yeah according to the manual, you are not supposed to lube the sliders. I'm guessing they're supposed to be some kind of lubricated metal of some sort. They don't work very well though, so doing the anti-sieze might be the best solution. I've tried all sorts of grease, and it all gets hard and sticky and makes the brakes stick.

And yeah, adjusting the drums makes a HUGE difference in brake feel! :)

[Klavier]

I put the anti-seize on because they were sticking when I bought the car. It's the same thick, black crap I put on my caliper slide bolts in the Ford. Her car stops fine, actually better since the caliper will release fully. I guess I'll just change the grease frequently so it doesn't gum up. Did you ever try dry-film graphite grease? That might work too.