Rear brakes

[f.boyle]

You all understand the lack of rear brakes so I am curios what you have done? I'm takeing the abs crap out and getting a new brake spring kit. try that I've got 1-1/8 wheel cylinders but the bleed screw is rusted in the abs so the fluid doesn't make it through. I'll see what thayt does then if I need more brakes I'll put in 12x3's I'll whip it yet!!

Frank

 

[Philip]

I would not reccommend the larger rear wheel cylinders.



The 12x3's is a good improvement. Do it.



If the ABS valve isn't letting fluid by very well something is wrong with it. Mine has no problem bleeding the brakes threw the ABS valve.

 

[f.boyle]

I don't think its letting fluid through could be I keep adjusting the breaks the wrong way? oh well I'll take care of it tomarrow. Have any of you heard about the speed sencor causing problems? I was reading about it in my manual that the 12+13 pins sometimes spread in 89-91's? the stealer has a new harnace for it so the book sais.

Frank

 

[Philip]

The fluid should go threw the ABS valve with now restrictions. The only time there is restriction is when the computer tells the valve to divert when it sees the ring gear stop turning in the rear axle. This is what the sensor is mounted in the top of your rear axle is used for.



How old is the master cylinder. It could be bad on the rear brakes and be why your getting very little fluid out of the ABS valve when trying to bleed the rear brakes.

 

[JLEONARD]

that I've got 1-1/8 wheel cylinders

would not reccommend the larger rear wheel cylinders

I have 1 1/8 cylinders in mine... . I replaced what was in there and they were 1 1/8

Jay

 

[Philip]

I have the 1" cylinders in mine. That is what NAPA showed in their book as the correct cylinder for it.



I do not reccommmend wheel cylinders that are larger than the system was designed for. The larger wheel cylinder will make for less aggressive braking on that axle.

 

[JLEONARD]

Larger cylinder = more force on the drums... . may take more pedal movement. ??? My truck stops fine like it is.

I remember when I was doing the brake job..... 2 weeks after I bought the truck... ...

One drum was complete toast so I decided to replace everything. Read all the numbers off the door sticker, under the hood, VIN, any number I could find... . none of the parts stores (including NAPA) I talked to could find drums that looked like what was on the truck, and the wheel cylinders they pulled were not the right diameter.

Finally my son helped me and thru a contact at ACME parts he asked for everything of every size that could ever fit on the rear of any Dodge truck in 91 and brought it all to my house. (There were 3 sets, sizes, of parts. )

So that included the 1 1/8 dia cylinders and the correct drums which were offset somewhat from the hub where the studs go thru. (the others were flat). I don't remember how wide the shoes were.

Maybe I have a 1 ton axle not 3/4 ton?

Anyway, that's my story. I feel better now!





Jay

 

[Philip]

Larger cylinder = more force on the drums

In a true hyd appilication this is true. BUT this is not a appilication where you have a pump that can apply more volume. You are working with a small limited volume pump (IE a master cylinder). If it can only supply 5cc of fluid per stroke. With a larger cylinder that means less total system pressure.



To give you a rough idea. Go into your kitchen. Get two different size glasses. Put one inch of water into the smaller dia glass. Then dump the smaller glass it into the bigger one. Now how far does it come up in that glass. This is the same thing your doing by over sizing a cylinder. If you can not increase the volume going to that cylinder with the same amount of stroke then you have a pressure drop.



Total master cylinder stroke is controlled by the front brakes on our trucks. The disks set how much pedal/ volume that is being sent to the rear brakes.



Also the bigger cylinders will respond slower to the apply pressure.

 

[dan brooks]

Originally posted by JLEONARD

... . none of the parts stores (including NAPA) I talked to could find drums that looked like what was on the truck... Maybe I have a 1 ton axle not 3/4 ton?

I know that feeling - took a couple trips and a lot of looking at different drums to finally find the right ones. Turns out they are the same as the 1-tons.

 

[JStraw]

Good subject! I recently did a 4 wheel brake job and found out that there are 3 different sizes that applied to my '93 model depending on how it came from the factory. Mine has the HD Bendix system which uses the largest pads/ cylinders. I also found out that there are different hubs and hub nut sizes. One size doesn't fit all applications. (numerous trips to the parts store and special orders found this out)



Thanks for the input phillip, I hadn't thought about the master cylinders being different to compensate for the fluid dynamics

 

[f.boyle]

I've had 1 1/8 cylinders in since I bought the truck and that was what was in it I dont think that is why I have no brakes though. 2 brand new masters didn't help. If I pump it once I have realy good front brakes but still no rear brakes. Think I will go to stealers in the morning and check out the speed sensor harnace it said in my dodge book. My lights ABS and BRAKE are always on maybe thats why? may grab 1" cylinders and 12x3's tomarow also. any other suggestions as of why those lights are on?

Frank

 

[paccool]

When I replaced the brakes in my 93 D250, the NAPA book showed the 1 1/8" as what was supposed to be there? Sure sounds like there are different books out there as well as Dodge playing around with different size components.

 

[f.boyle]

Pretty sure that was the book for my truck, I'll check an maynards today. I think I'm going to replace the shoes and the wheel cylinders tonight see how that goes then monday if all else fails I'll resort to the stealer :{ .

Frank

 

[Philip]

The GVW and build date has a lot to do with some of the part selection. Just about all parts I get from NAPA for the chassis they ask me for the build date.



I don't know about you guy's with the 1 1/8th cylinders. But on my 11k GVW chassis I can feel the back brakes working even on a normal stop under slow speed light brake application.





f. boyle



While you are picking up parts. Get a new self adjuster kit added to the list. I all ways replace all the support parts when doing a brake job. I saw in a earlier post you were doing return springs. The self adjust parts are just as important as the other small parts to. Unless you like crawling under it and adjusting brakes.



I can't help on the ABS to much. Mine has been unhooked since I got the truck. I all so have no plans on repairing it either.



You might also want to look threw this thread. There is some good reading on the tests for the ABS and brake light troubleshoting.



https://www.turbodieselregister.com/forums/forumdisplay.php?daysprune=&forumid=11&x=15&y=6

 

[f.boyle]

did it every thing but 12x3 shoes which i got today, and the e brake stuff is new and polished! got some electronic connectror cleaner to spray on the connections. but where did you unhook the abs? at the puter? doesn't that also kill your intake heaters?Did you rout the brake lines around the rwal valve or leav it be?thanks a bunch

Frank

 

[Philip]

The ABS valve is still on mine. It has not been bypassed. The wires going to the speed sensor in the rear axle were broken when I got the truck. My ABS light has never came on and it has a good bulb in it. I checked the bulb the last time I had the dashboard apart.



With my speed sensor disconnected I have no idea why my ABS light isn't on. But I am not going to grip about it.

 

[f.boyle]

ok then. how much brake travel do you have? I am in the middle of tearing my truck back down for new 12x3 shoes after I'm done and road test it I will start to go down the list from the other post you told me about. I have that wire on order from the stealer back ordered of course. but which wires are cut/broken and where? They might happen to get cut. Yoiu are realy helping me out salot I hope I can repay the favor. I'll post as soon as the road trip is complete

Frank





* * *



f. boyle: I would respectfully request that you refrain from indiscriminately using the reference, stealer. Posting facts/details is fine - absolutely no problem. If you have any questions regarding this request, please e-mail me at: rpatton@ix.netcom.com.



Thank you.



Robin

TDR Admin

 

[Philip]

In the top of your rear end housing is a senser. This senser is what tells the computer you are sliding rear tires and then the computer kicks in the ABS valve. The wires on mine were broken off flush with the senser housing.



Do not cut your wires. There is a wiring connection plug over by the ABS valve. Just unplug it there.



I don't know how much travel I have. I have not measured it. On a rough quess. At 2" the brakes are applying and 4" they are locked up. If I think of it tomorrow I'll measure it.

 

[tateinca]

Adjust those suckers

Frank,

When you said you get a good pedal on the 2nd

push on the pedal, that indicates to me that the

adjustment is way off. Try the other direction

and see if it makes a difference.

Good luck, Hugh

 

[f.boyle]

Ahhh

Its all good!Got the new 12x3's, springs, and adjusters on/in, filled the rearend with oil, Scheafer's best on earth took a road test stops like a 2003 for less The guy at the NAPA said the HD version W250 was supposed to have 12x3's and 1 1/8 cylinders. where the heck was he before??? At NAPA!!!You have to use NAPA!If you get it from any where else the truck knows and rejects it(the part) like a transplant from the wrong bloodtype!Thats just the way it is, ya think? fixed the stopping part, but what to do about the abs and brake light??



Phillip,

Where and what wires are cut on your truck??I'll do that if the other post you sent me to can't solve it. Don't care much for ABS systems any how!! I've heard it said that the greatest computer in the world is the human brain! so mine must at least be better than that crystler plastic crap behind my trucks glove box!!Right



Now on to tach, boost, EGT, and torching my 96"x108"duallie flat bed down to 84"x96"single size. also have to move my stack in to bed shorten in my westcoasts. then on to fun stuff new clutch from bluechip,intercooler.

Frank

thank you all very much for the help. I was really getting /:{