Bleeding Brakes

[Cooneytoones]

Sent: 4/16/2005

A question???... Good Tip if it'll work...A guy who worked as a brake specialist at Midas Muffler for 30 years, told me, to bleed brakes all by your lonesome, you can leave the top off the master cylinder, crack open the bleeder screw (one wheel at a time) and gravity will take care of the air. In other words, the air will come out and into the
reservoir of the master cylinder. Claims you'll be able to see the bubbles. Told him not on mine. As you all know you can't see the level in MC. He said It may take a few minutes per wheel, but as long as you keep the MC topped off, he claims it'll work evertime...Has anyone tried this? I sounds logical, due to the MC being higher than the bleeder.
Timmy

[The_Handier_Man1]

Sent: 4/16/2005 3:59 PM

The brake fluid will drain out of the MC and thru the wheel cylinders by gravity somewhat but if I do it myself I use a small hand held vacuum pump ($30.00 or so). I'm not sure if the air bubbles would come thru all the bends like the boosters( mine has two of them)  without some help.  You want the air out of the lines not in the lines.    Les

[Derrek]

Sent: 4/16/2005

Hi Timmy

I have used the "gravity bleed" method many times. I did it last spring on my motor home after reworking the entire brake system. Les may be right about air becoming trapped in the boosters, if you have the style of system with the booster on the frame rails. Mine is a M600 chassis with the hydraboost (pressure from the power steering pump boosts the brakes rather than engine vacuum)so I didn't have that issue.

I have also bled brakes using a "one man bleeder" method. This uses a piece of rubber hose that fits snug on the bleeder screw and the other end goes into a jar (or some type of container) partially full of brake fluid. (The hose must remain submerged in the fluid) As you pump the brakes brake fluid will be expelled out of the bleeder and into the jar. Any air that comes out will float to the surface of the fluid. When you release the pedal brake fluid will be sucked back into the system rather than air. I usually fill the master resevoir and pump the pedal 10 times or so then refill the master resevoir and empty the jar.

You can also use the vacuum pump method that Les mentioned. I have also used this method in the past, but seem to have better luck with one of the above methods.

Here is the vacuum pump:
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=92474

                                                                            Hope that helps
                                                                                 Derrek

[Cooneytoones]

Sent: 4/16/2005

No Les I don't have a vaccum booster, so except for some twist and turns along the chassis, it should work...
Yea Derrek...Thanks, Helps a bunch..I have an M500 Chassis, same system as yours, P/S Booster for brakes..
Started to do mine today, Had it all jacked up, and on stands, but the grass area was way too soft, and over night it settled too much, so,  had to jack it up again ...then let it all down so I could move it and put it on more solid ground....Jacking the damn thing is the hardest part of the job... going to try the gravity method, but I ordered on of those pumps from Harbor Freight....I just love Harbor Freight....thanks again,
Timmy

[DaveVA78Chieftain]

Sent: 4/17/2005

One problem with the vacuum pump method is that it can suck air in around the threads of the bleeder screw.  Doesn't harm anything but can fool you into thinking there is still air in the lines.  The nice thing about that pump is that you can also use it for checking things like vacuum advance diagphrams or egr valves, etc..  I prefer the one man bleeder method using the hose and jar or you can also pick up a one man bleeder kit from almost any auto supply.  Comes with a clear hose which helps you see if there is air in the line if someone is pumping the brakes for you.  It also has a magnet attached to allow placing it in a convient location.  Only down side with it is you only can pump the brakes about 6 times before the plastic jar fills up.

Dave

[SmallDiscoveries1]

Sent: 4/18/2005

I did the gravity method on a 72 corvette. It is the only thing that worked for me.

[smp5937]

Sent: 4/20/2005

OK, all this sounds really good, and I have never used a pump OR a one-man system, so I have a question:

DaveVA78Chieftain said "One problem with the vacuum pump method is that it can suck air in around the threads of the bleeder screw.  Doesn't harm anything but can fool you into thinking there is still air in the lines."

Now, if the rubber hose on a pump can do that, and you basically rig up a one-man system the same way, with the bleeder screw loosened and a hose on it, won't it also pick up air as it sucks in the fluid (around the threads)??

[Oz]

Sent: 4/20/2005

Just went through this process with Dave.  Very easy, even easier if you have someone pumping the brakes while you do the stuff underneath. 

You put a little fluid in the bottom of the bottle, just enough to cover the end of the tube going in.  The bottle also has a magnet to put it against the frame. 

It won't suck any air back up because of the fluid in the bottom of the bottle and you're not using forced vaccum either. 

Just be very careful how many pumps you do.  The back may take 5 or 6 til the bottle is full and the front may only take 4.  Be sure to re-fill master cylinder after every bottle full.

Very cheap and easy.  Like me! - SleazySob

[denisondc]

Sent: 4/20/2005

My reservation about the gravity method. Two brake hoses run to my rear axle, and from there they both feed the left and the right sides, two wheel cylinders on each side. Therefore it has 2 brake lines running up and over the differential housing. When I remove the wheel cylinders on the curbside last year, those lines had the chance to get air in them. The fluid would flow from the frame, through the two rubber hoses, and up and over the "hump" above the differential housing, but unless I had enough pressure to flush the fluid through fairly fast, the air that was on the far side of that hump would let the fluid run past it, to fill the wheel cylinders -- leaving me with an air bubble in the tubing in the middle of the rear axle.
Which is why my brake pedal has about 2 or 3 inches of mush now, even after one bleeding evolution.

[Cooneytoones]

Sent: 4/20/2005

Thanks Denison,
I knew there would be a kink to the gravity method. It would work on a simple system like a corvett or a small vehicle....but, I have the same system as yours with dual brake cylinders. And just from looking at the set up, it seems that the dual BC's work in tandum, (only the top cylinder has the bleeder screw) Without some type of pressure, air does not rise very easily, Like you said also,  I too do not think there would be enough pressure to push the fluid to the top BC, or out of the tubing meandering accrosed the rear end...It may do it eventually, but may take an hour/hours.
thanks again.....Denison hits another home run.......
He's one hell of a Win-geneer.....
Timmy

[jddrivfour]

Sent: 4/22/2005

The method I have used is to have your helper pump the brake pedal several times quickly and then on the last one, keep the pressure on. I open the bleeder screw under pressure. Close screw then let pedal up slowly. This compresses the air in the fluid column and it gets pushed out with the fluid.

[DaveVA78Chieftain]

Sent: 4/22/2005

smp5937 said "Now, if the rubber hose on a pump can do that, and you basically rig up a one-man system the same way, with the bleeder screw loosened and a hose on it, won't it also pick up air as it sucks in the fluid (around the threads"

I have never really noticed the system pulling air back into the system past the bleeder screw threads.  I suppose there is not enough suction in the line to do it.  It would be a very very small amount anyway.  This is a variation of the method jddrivfour just mentioned.  jddrivfour's method is the one you normally hear about.  The one man method is mainly used when you don't have that helper to pump the brakes for you.  Also, it keeps air from being pulled back in via the rubber tube.  I used it to teach Sob how to bleed the brakes either with or without a helper.

Dave

[Derrek]

Sent: 4/23/2005

Denison,

Your motor home chassis actually has two sets of brake lines running to the rear brakes?

My M600 chassis has the dual wheel cylinder setup, but is not like the one that you described. Its strange that Dodge would use two different setups for the dual wheel cylinder rear brakes. I wonder if this is because of the difference between the Hydroboost and Vacuum boost systems??? Interesting.... Below is a diagram of the rear brake setup on my M600 chassis.

Timmy, if your M500 has the same setup (there were two different rear axles used on the M600 chassis) you should be able to use the gravity bleed method. I simply cracked the bleeder screws open and could watch a few drops of fluid drip out, followed by a few air bubbles, etc. I just left them drip and topped off the master cylinder every 15-20 min. (During the NASCAR race commercials of course!)

[denisondc]

Sent: 4/23/2005

I know that the M400 chassis with drum brakes on the front axle had the double brake lines going to the rear axle. I also know that some other Dodge motorhome chassis had 4 wheel cylinders on that back axle, but the wheel cylinders were connected via a short brake line that ran from cylinder to cylinder Inside the brake drum.
I assumed it was Dodge specifying which axle rating they wanted, from Dana/Spicer, and the actual brakes that were on it were probably whatever Dana/Spicer had determined were the best setup at the time, based on the front axle rating that was specified.
Both good systems though.

[Cooneytoones]

Sent: 4/23/2005

Yep Derrek.....Mine is exactly the same as yours, a hydo-boost system...which tee's off the main steel line from the rubber hose, and runs to both bottom W / C 's accrossed the rear axal.....then goes up the backing plate to the to top Cylinder and the bleeder screw is on the top of the top W /C. I think they called it's called a Twin-Plex System (Two cylinder floating shoe rear brakes) ....I have disc brakes in the front. My only problem now is I hope I can get the lines undone without damaging the tubing (even using flare wrenches).....they have lots of rust on them...been cleaning,  praying & spraying w/ WD-40. I think they'll come......
Nice diagram.....How'd you do that?
Timmy

[Derrek]

Sent: 4/23/2005

Your brake lines will probably come loose without damage, if you are careful. Being from Ohio, we are lucky to get 10-12 years out of a set of brake lines. (The salt just destroys them!)
I was fully prepared to replace all of the steel lines when I went through the brake system last spring. To my total amazement, the steel brake lines were in excellent condition and the fittings un-threaded with a little bit of penetrating oil and patience. Not too bad for a 1978 chassis, granted it probably didn't get much winter time use before I owned it. I cringed at the thought of the salt getting on the chassis during our Feb trip to Florida, but wadda ya gonna do..... we had to go to the Daytona 500!

Yes, being able to draw a diagram is very neat! John (Heavy Truck Hauler) used this several times in the "little or no vaccum thread". He and Dension explained how I could do it:

It is done using Microsoft paint. Go to the start menu and click "Run". Then type in mspaint.exe, then click OK. You can create a drawing or diagram and save it to your documents, then load it onto the page using the "insert picture" feature in tool section on the top message box.

Good luck with your brake job. Here is a thread that I posted at the Apollo owners group when I did my brake job... http://groups.msn.com/ApolloMotorhomeowners/brakes.msnw?action=get_message&ID_Message=317

You may want to perform a similar test so that you can see the improvements and keep tabs on your brakes in the future. I plan to do a similar test each spring, to ensure my brake are up to their full potential.

Keep in mind that my motor home is built on the 16,000 lb M600 chassis and weighed in a 15,800 before our Feb trip(......she's a big ol' girl) so you numbers will vary depending on your Winnies weight.

[jddrivfour]

Sent: 4/24/2005

The best penetrant I have ever used is PB blaster. This stuff is amazing. WD-40 not even close.. TThis PB penetrant reacts with the rust and usually within minutes goes completely thru the length of the thread. You can find it in the chain auto stores-Checker etc. Please give it a try.

JD

[Cooneytoones]

Sent: 4/23/2005

Thanks Derrek,
Mine is an M 500 so weight wise, it's only 1k lbs short of yours .... a real big girl too @ 30 feet long. Taking my time. I've got till May 22 to get her ready for the Coke-a-Cola 600 in Charlotte. I'm ready to go racin'we're also going to Daytona for the Pepsi 400 in July....Hope to see you at a race one of these days....
Thanks for the info...your thread on your brake job is great....Thanks,
Timmy

[brakeparts]

Sent: 4/25/2005

Guys, the M600 has a whole different rear end than an M500. The shoes are the same, but not the wheel cylinders, seals, weight rating, or rear brake hose from the chassis to the junction. They do share the same brake shoe hardware, however.

These vehicles are at least 1500 lbs apart in GVWR. M500's run 14000 or 14500, the M600's run 16000 or 16500. M500's use a Spicer rear axle, the M600's use a Rockwell.

That about sums it up - oh, the drum front brake trucks use entirely different hydraulics and shoes than any of the disc brake trucks. The axle parts are not interchangeable either. FYI,

Geoff

[Slantsixness]

Sent: 4/27/2005

Ok, so everybody's worried  over bleeding brakes.... the little bottle is too small....

For years, I've been using a large (gallon?) glass pickle jar (mount olive kosher dill pickles if you must know...) filled to completely cover the tube with a little used brake fluid, I used a sink disposal gasket and sealed the cap, drilled a hole and put a fitting in it that attaches to a stiff tube (clear) that goes to the bottom, the cap is vented with another fitting, then the clear brake line bleeder hose attaches to it. It cost about $2 for the hose and fittings (I think the pickles were around $6 but we ate them long ago!).
Since the brakes are hard to bleed by oneself, sometimes I will just use new brake fluid in the jar, leave a bleeder open, and SLOWLY pump the brake pedal, with the bleeders only slightly cracked open. this allows the master cylinder to use the hydraulic pressure to flush out the bad fluid and air, and limits the release "fluid draw" from the jar.

In any case, brake fluid goes BAD. after 30 some odd years, whatever original brake fluid that is in your brake lines is probably doing more damage to the brake lines than you want to know. That's why it's brown or black!

So, I change my fluid completely, until it runs "clear" on each bleed point. Then I go back around and "bleed" again to make sure I get every last bubble of air out.

Here's something important:
DON'T Bleed your brakes in one day if you have deteriorated fluid (more than 5 years old) and do a fluid change. Wait 24 hours after you change the fluid to allow the fluid to settle. Then bleed again. You'll be suprised when you find air in the system again the next day!

I do not like Power or gravity bleed systems.
Here's why:

1. Gravity bleeding will trap air in the proportioning valve. (which resides ABOVE the brake lines, although below the Master cylinder)
2. Power bleeding (that hand pump thing) leaves a significant amount of air throughout the hydraulic system no matter how long you sit there and pump it.

I do remeber the "old" way to gravity bleed, which without a proportioning valve, did work....
Jack up the car in the front, open the rear bleeders and wait... then close them and open the front... and wait.
run out of brake fluid.... then you have to repeat the whole process. Nice Idea, but it won't work with the safety proportioning valve (and ALL Winnies have them)! The valve has a safety that will shut off fluid to the rear brakes! that's why your brake light comes on! 

So, there's my long winded opinion.

Tom

[olivereaman]

Sent: 4/28/2005

jddrivfour, You are absolutely correct about PB Blaster, I've been using it for over 10 years now, and NOTHING comes close to it!! If PB Blaster won't loosen it, you have a serious problem. It's the best I've found, and we try everything that comes through the door from the vendors!

The logic is sound, as long as you remember what the purpose that 's' trap under your sink is for. Same thing will happen with a brake line and brake fluid.

[ClydesdaleKevin]

Sent: 4/29/2005

Here is my question to all of you Winnie-gurus out there: 

I just went through the breaking system on the Ark, and found that the PO did most of the work for me.  There are several new break lines, every wheel cylinder except one looks brand new (not even rusty), the shoes look relatively new (lots of meat left on them), the springs and hardware is obviously relatively new (surface rust), and there is only surface rust on the inside of the drums (I cleaned them up in about a minute each with fine emory cloth).

The only thing visibly wrong was the vacumm hoses going to the boosters, and between the boosters.  I replaced all these (still haven't found a source for that little air filter, but if any of y'all know where I can get one, I'd be much obliged).

Just like the Winnies, my Futura has no real access to the master cylinder reservoir, so, since we are recarpeting the cockpit, I'm going to cut a trap door over it.

This leads me too my question:

When bleeding the breaks, should I do it with the engine running, or with the engine off?  It sounds like a stupid question, but I'm curious about the role the fluid lines play as they go to and leave the boosters.  Since they operate on manifold vacuum, will the lines still bleed thoroughly when the engine is off?

(oh yeah, another lucky break!  The wheel bearings and seals also look fairly new, with newish looking grease.  I cleaned them all thoroughly with solvent and repacked the heck out of them...drums spin like a top!)

(a second "oh yeah"...Any suggestions on how to lube the parking break cable, short of removing the darn thing?)

Kev and Patti Smith

[denisondc]

Sent: 4/29/2005

I would remove the parking brake cable to lube it. I did and soaked it in kerosene for a couple of days in a tub big enough for me to coil it up and lay the coil flat. Then I hung it up vertically and dribbled oil into the top, sliding it back and forth a few times each day. Mine was badly stuck, and the sliding action was done with the aid of Big Levers and C clamps at each end. After several days of my hoping it would free up it snapped in the middle â€" right where it had been exposed to the heat from the exh. manifold. The new one cost about $75 from dartman67BB@BBaol.com, except of course drop the BBs from the email address. I also took the drum off the end of the tranny and got those shoes relined. Of course I had done without that handbrake for a couple of years first; the safety inspector never checked the handbrake.
I do my bleeding with the engine off, just so I don’t have to endure the heat and racket. It probably takes a little longer as a result. I bleed the hydrovac boosters before I bleed the wheel cylinders. Some boosters actually have 2 bleeders each, but mine have onle one bleeder each.
That little inlet air filter cartridge is a Fram CA-2 PL1. That was the # on it in 1972, and someone on the site said they were still available in a decent parts place. If not I have a used extra one that I would trade for a souvenir; a piece of the pressure hull from the San Francisco.
Any small air filter could be adapted to the purpose â€" something from a lawmower maybe? Im still using the original - talk about rust covered!

[DaveVA78Chieftain]

Sent: 4/29/2005

"souvenir; a piece of the pressure hull from the San Francisco"

Now what you plan to do with HY-80 steel Dave?  I take it you have seen all the pics from that mess?

Dave

[denisondc]

Sent: 4/29/2005

Yes I have seen pictures of the damage.