slowindown
Junior Member
This will be a bit long but there's a good bit of info for troubleshooting purposes.
I have a 2007 ram 1500 4 door 2wd 5.7 with 230,000 miles. I bought the truck new. Until now, no one has touched the brakes but me and that was at least 100,000 miles ago when I replaced front hubs, rotors and front and front pads. Some time later I replaced the rear pads but not the rear rotors. This truck has abs but the module only has one line running to it from the master cyl and one line exiting that goes to the rear brakes. So I assume the rear brakes are technically the only ones with abs, all 4 are disc brakes tho. This is a southern truck so no rust underneath.
Anyway, I took it to the front end shop recently for an alignment, ball joints etc and they noticed the brake pedal was dropping and said if I brought it back they would replace the master cylinder. So I brought it back later. A new master cylinder didn't change anything. In fact, they tried two from Oriellys and a better brand they had to wait several days to arrive (I forget the brand). None of the three were any different from the stock trw unit in functioning (except that the fluid level sensor on all 3 new ones said it was low on fluid - the old one doesn't do that - odd).
So, this is what it does: push the brakes and they work but the pedal continues to near the floor. But it does stop. Also if your at highway speed when you initially hit the brakes there is a shudder for a second or 2 that goes away (feels like from the rear - was assuming it was a warped rotor but no longer sure). You can make the brakes work close to normal by giving them a good double tap - the pedal stays higher but will eventually go down. The pedal will drop whether the truck is cranked or not.
This truck has abs but the module only has one line running to it from the master cyl and one line exiting that goes to the rear brakes. The line furthest from the booster is the one that feeds the abs module. The mechanic told me they were getting brake fluid at all four corners when they bled them. The mechanic said that all of the calipers seemed to be functioning normal and not sticking - I believe he said he tried some different calipers too. He also said that the rubber lines did not appear to be swelling and that he was stumped.
No abs or brake light has been on (except the fluid level from the master cylinders that the mechanic tried). This shop has been in business a long time, is owned by a nice guy and I've never heard anything bad about the shop. Plus he wouldn't take anything for all of the hours he has put into it. But he did say that he didn't know a lot about the workings of the abs system (he can re-plumb around the abs unit if I want him to). But that's my last option. I brought the truck home to try and fix it myself.
I know very little about abs although I have replace a module in my daughters volvo when no fluid would go to one of her rear calipers. It had many more brake lines than the one in my truck. I'm wondering if a bad abs unit can cause this issue I'm experiencing or if not, what could.
Thanks
I have a 2007 ram 1500 4 door 2wd 5.7 with 230,000 miles. I bought the truck new. Until now, no one has touched the brakes but me and that was at least 100,000 miles ago when I replaced front hubs, rotors and front and front pads. Some time later I replaced the rear pads but not the rear rotors. This truck has abs but the module only has one line running to it from the master cyl and one line exiting that goes to the rear brakes. So I assume the rear brakes are technically the only ones with abs, all 4 are disc brakes tho. This is a southern truck so no rust underneath.
Anyway, I took it to the front end shop recently for an alignment, ball joints etc and they noticed the brake pedal was dropping and said if I brought it back they would replace the master cylinder. So I brought it back later. A new master cylinder didn't change anything. In fact, they tried two from Oriellys and a better brand they had to wait several days to arrive (I forget the brand). None of the three were any different from the stock trw unit in functioning (except that the fluid level sensor on all 3 new ones said it was low on fluid - the old one doesn't do that - odd).
So, this is what it does: push the brakes and they work but the pedal continues to near the floor. But it does stop. Also if your at highway speed when you initially hit the brakes there is a shudder for a second or 2 that goes away (feels like from the rear - was assuming it was a warped rotor but no longer sure). You can make the brakes work close to normal by giving them a good double tap - the pedal stays higher but will eventually go down. The pedal will drop whether the truck is cranked or not.
This truck has abs but the module only has one line running to it from the master cyl and one line exiting that goes to the rear brakes. The line furthest from the booster is the one that feeds the abs module. The mechanic told me they were getting brake fluid at all four corners when they bled them. The mechanic said that all of the calipers seemed to be functioning normal and not sticking - I believe he said he tried some different calipers too. He also said that the rubber lines did not appear to be swelling and that he was stumped.
No abs or brake light has been on (except the fluid level from the master cylinders that the mechanic tried). This shop has been in business a long time, is owned by a nice guy and I've never heard anything bad about the shop. Plus he wouldn't take anything for all of the hours he has put into it. But he did say that he didn't know a lot about the workings of the abs system (he can re-plumb around the abs unit if I want him to). But that's my last option. I brought the truck home to try and fix it myself.
I know very little about abs although I have replace a module in my daughters volvo when no fluid would go to one of her rear calipers. It had many more brake lines than the one in my truck. I'm wondering if a bad abs unit can cause this issue I'm experiencing or if not, what could.
Thanks
