Engine/Transmission (1994 - 1998) adjusting parking brake

[vc]

I noticed today my parking brake is not holding as good on the boat ramp as it usually does. So I glanced at my manual for adjusting the parking brake and what I understood is that I actually need to check and adjust the drum brakes which in turn would make the parking brake as effective as possible. Is this correct? I'm used to actually adjusting the parking brake cables/mechanism to reset the p-brakes on other vehicles.

Thanks.

vc

 

[illflem]

Adjust the drums first and your e-brake will probably be ok.

 

[vc]

ok Bill - thanks. I'll check on that tomorrow and go from there.

vc

 

[MikeR]

My 95's drum adjusters are as tight as can be, but my P-brake pedal still requires being pushed as far down as possible and it barely holds on hills. Where do I adjust the P-brake at? I looked at where the cables join together directly under the bed along the frame rail, but it looks like only one cable would tighten up if I cranked on the only nut there.



-Mike

 

[illflem]

My '95 manual says,in bold letters, that p-brake adjustment is only necessary when the tensioner or cable has been replaced or disconnected. The instructions are over half a page, much of which is adjusting the brakes and pulling the drums to inspect for worn/broken parts. When the manual finally tells you how to adjust the brake it says to tighten the equalizer (threaded rod were L&R cables come together) only 1/4" with the brake engaged then jack the rear and make sure there is no drag with the p-brake released. Don't know quite why but my last sentence took the manual two paragraphs to explain. I've never had to adjust my p-brakes with over 300k combined miles on my rigs.

 

[dremelts]

VC,



I, for one, will NEVER trust my p-brake again - especially on a boat ramp. See the thread that I started a couple of weeks ago about my p-brake releasing itself after I had parked and walked away from the truck. One of the people who responded to the thread actually sank his truck at a boat ramp.

 

[redramnc]

Somebody can correct me if I am in error about this one:



I have always found the P-brake to be much better at holding against forward movement than stopping it from rollng backwards. I have many, many miles on Dana rearends and they have all seemed (at least to me) to be much better about forward roll hold than backward. I have always kept brakes adjusted so I don't think it is slop in the innards causing this. I assume that it is the way the brakes pull the internals that preloads them better on the forward roll than in the reverse direction.



Anybody have any good ideas on this or have I lost me mind?

 

[illflem]

redramnc, your mind's ok. Most every vehicle I've driven with rear drum parking brakes holds better forward. Ever notice how you can back up while forgeting to release the brake but have a hard time doing it going forward? Think it has something to do with the self adjusters.

 

[Bill Stockard]

You guys have stumbled upon the phenomenon of self-actuating or self-energizing hydraulic drum brakes. The brake shoes tilt ever so slightly with the forward rotation of the brake drum which “wedges” the shoes tighter against the drum. If I remember correctly, this was an invention of Walter P. Chrysler when he introduced hydraulic brakes on the automobile in the 1930s.



For more information in laymen’s terms, here’s a web site that explains how it works: http://www.howstuffworks.com/drum-brake1.htm



Bill

 

[vc]

Well guys,

I checked my brakes today and the rear drums are set correctly - I can just barely get a little rub when I turn the wheels by hand. So I then tightened down the adjuster nut on the tensioner about 3 turns and rechecked for drum rub. Still the same and then a check on the driveway seemed to be a little better. Also while the rear end was up on jack, it took about two less "clicks" on the brake pedal to get the same grab as before.

By the way, ever notice how it's a bit harder to turn the wheels when it's a limited slip?

Thanks.

vc

 

[vc]

line lock device

No doubt this has been discussed before, but has anyone found some sort of device that can be tapped into the brake line that would trap line pressure if you apply brakes then activate this line lock so that in essence you have a better temporary parking brake - even for the front brakes? Seems like this would be the way to go. This is basically how the parking brakes on the planes I fly work, and work good at that.

thanks.

vc

 

[illflem]

vc, see if this is what you're looking for http://www.jcwhitney.com/SearchCatContainer.jhtml?_requestid=69255

If this link doesn't work go to www.jcwhitney.com and search for 85RQ6592Y

 

[Bill Stockard]

vc,



Are you thinking about a Mico brake lock? You press down on the brake pedal and flip the lever to lock the brakes which holds the hydraulic pressure on the brakes and prevents the fluid returning to the master cylinder. I've seen these in a few medium duty trucks. Usually near the handle there is a big warning decal not to leave the vehicle unattended with one of these in use. If the fluid pressure ever leaks down a slight bit, the brake holding ability is lost. The Mico brake lock is seldom in used in trucks because of the safety factor.



Bill

 

[vc]

Bill (illflem),

thats pretty much it. From the description on JcWhitney it looks like I would have to figure out how to activate it from the cab since I would have to push the handle down to activate it.



Bill Stockard,

you are correct on what I'm looking for. I realize if it leaks it would let go. Hopefully I would only use it for a few minutes when I launch or retrieve my boat on the ramp.



thanks.

vc

 

[illflem]

vc, you could use a plunger type solenoid to push the button, starter solenoid comes to mind.

 

[redramnc]

Racers use electrically-activated line-lock solenoids all the time. The solenoids are no different than our fuel shutdown solenoids, just designed for the pressure generated by brakes.



I would not rely solely on them for holding but as an addition to the P-brake they should provide an excellent safety margin.



Of course, good chocks are hard to beat. Somewhat cumbersome at times, but effective as it gets.

 

[vc]

I was at my Summit Racing catalog and they sell several different line locks that are electrically activated. Also by typing in line lock into the search engine it came up with a couple others. This looks like the route I will go for the front brakes to "back up" the rear parking brake. Thanks for all the help here guys.

vc