not enough rear brakes effort

not enough rear brakes effort

Posted in the Isuzu NPR Forum

rafael

Heredia, Costa Rica

#1 May 1, 2011
Hi every body. I have a problem with my isuzu npr hd. Rear brakes dont work well, they have a lack of effort, I already check the break shoes, brake drums, and they seem to be right.
I was wandering if the problem could be the load sensing valve seized, its the only thing left to check. Do I need to replace it, or it could be unseized with some wd40, or maybe it needs to be adjusted?. My truck is a 1999, no abs.
Front disc brakes do all the job, they used to get so hot after a few miles on the road. I hope you can help me, excuse may bad english I am not from US.
So please if you could tell me how to adjust, or unseized it, thats will be great.
Thanks

Since: Oct 11

Hartford, CT

#2 Oct 10, 2011
I have the same trouble. How did you fix it ???
rafael

Palmares, Costa Rica

#3 Oct 10, 2011
I have heard that removing the load sensing valve its not safe but I did it.I put all the pipes together I used the same housing of the valve to do it, just removed all the stuff inside and sealed it in the bottom by using broze welding . Also Isuzu trucks have a check valve located next to the master cylinder, when it stops working it affects rear brakes effort, I removed that check valve too and now brake fluid runs freely to the rear circuit.

Well, good luck. Just realize that make changes to the original brake system brings risks.
Gorkie

Surrey, Canada

#4 Apr 21, 2013
You need to adjust the rear the brakes every oil change
Jesse

Houston, TX

#5 Nov 11, 2013
It may just be out of adjustment. There are holes on the back of the drum assembly that have rubber caps on them. When you pop them off (using a flashlight) you can easily see a pin-wheel. The backing plate will show you the direction to loosen, so use a flat head to turn the pin wheel in the correct direction. If this does not work, check the proportioning valve/metering valve as well as the pressure differential switch.
Richard CT

Cape Town, South Africa

#6 Feb 1, 2015
worn leef springs cause this problem as load sensor pika up that the body of the care ill loaded
donnie walley

Deridder, LA

#7 Mar 16, 2015
i have a 1999 npr the brake pedal is soft when i am stopping and the power booster light comes on.done replaced master cyl.and brake booster has not help anything.what else should i do?
james harvon

Wilmington, DE

#8 Apr 14, 2015
I didn't know that the rear brakes had to be adjusted that often. For now on I will make sure that our rear brakes are adjusted at least each oil change. The last thing that I would want is to have any brake issues on the road. These adjustments should help my truck equipment last much longer. http://www.hawaiispringsupply.com/honolulu-hi...
rodney

UK

#9 May 27, 2015
rafael wrote:
I have heard that removing the load sensing valve its not safe but I did it.I put all the pipes together I used the same housing of the valve to do it, just removed all the stuff inside and sealed it in the bottom by using broze welding . Also Isuzu trucks have a check valve located next to the master cylinder, when it stops working it affects rear brakes effort, I removed that check valve too and now brake fluid runs freely to the rear circuit.
Well, good luck. Just realize that make changes to the original brake system brings risks.
Hi and when you did that,did the brakes come right
rodney

UK

#10 May 27, 2015
Hi I have the same problem with my truck the rear brakes don't hold that well I put new drums and Lining still did the same then I changed the load sensor still doing the same thing please can your help me with some of your plans.even changed the master

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