Drove my truck low on brake fluid now dash Brake / ABS light is on

[TXd150]

I drove my truck the furthest ever (60 miles) since the new engine install and didn’t check the brake fluid level. I guess the fluid level was low and using the brakes made it even lower. Now the dash brake light and ABS light stay on even after filling it with brake fluid. The brakes work fine but Im just starting to hear the wear indicator squeal. I plan to put new brakes before driving it again but would like to fix whatever is making those dash lights stay on first.

 

[Curmudgeon]

I'm not a mechanic by trade but been working with my hands all my life and have played with my vehicles forever so I have 2 thoughts...

1. If the pedal feels good as you suggest there is probably no air in the system, just thinking you might want to plan on bleeding the system while you're doing the brakes anyway. This is not likely to resolve any dash lights.

2. I have learned, often the hard way, you might have to drive it a bit before any lights/codes will clear. Sometimes codes have to cleared through the OBD port. I know I can get tire pressure readings to show accurately in 1 mile or less, but codes like emissions-related can take a longer drive. Brakes/ABS being safety you might have to drive a couple dozen miles or so.

Seems like a stretch to me that a simple low fluid would necessitate repairs but everything should be up for consideration given the truck's age?

Anyway, my $0.02. Drive it first for a bit, as long as it's safe to do so. Good luck!

 

[TXd150]

I believe there’s more to this. I installed new front calipers and brake pads, looks like it needed to be done. I bled the brakes and the brake / abs lights went off. After driving it the pedal went all the way down and I had no brakes. I returned home and checked for leaks but didn’t find any, the brake/abs lights were back on. I bled the brakes a few more times but still had the same problem. I just bought a brake master cylinder and plan to install that next to see if it helps. Any advice or tips would be appreciated

 

[TXd150]

Put the new master cylinder in tonight and found that the old one was leaking fluid into the booster. There must be another leak somewhere because the pedal goes straight down while the engine is running. It does build a little pressure while the engine is off but as you press the pedal it still goes all the way down.

 

[Mojo88]

Put the new master cylinder in tonight and found that the old one was leaking fluid into the booster. There must be another leak somewhere because the pedal goes straight down while the engine is running. It does build a little pressure while the engine is off but as you press the pedal it still goes all the way down.

After a couple of pumps, the brake pedal is always gonna feel a LOT firmer with engine off. This is simply a result of no more assist from the booster.

If your pedal is going down with engine running, then this most always means you've got air in system, or you've got a leak. The leak should be easy to detect, by pumping the brake a few times and looking. To confirm it's a leak, carefully mark fluid level in the M/C (hopefully you 'bench bled' the M/C prior to installation), and then pump a bunch of times and look again at the fluid level. If it's dropped, then you know you have a leak. If fluid level is same, but pedal still goes to floor, you likely have air still in system.

I owned two service stations back in 70's and 80's, done thousands of brake jobs. Looks like you have a '87 truck?? Those brakes are pretty simple hydraulic systems. Not sure if you have ABS, but if you do, you may need to cycle that system while bleeding (I'm not familiar with that year).

My initial guess is that you have a bunch of air still in system. Perhaps you're not bleeding correctly. In the old days, I always had a helper bleeding brakes, but BOTH people need to know what's going on and they need to be in perfect sync, otherwise air keeps getting introduced.

Nowadays I use Motive pressure bleeder, which is virtually foolproof, and I can EASILY bleed brakes by myself.

 

[TXd150]

The truck I’m working on is a 2001 Dodge Ram 1500 3.9 w Automatic transmission. The 87 Dodge truck is long gone and I miss it every day. I did bench bleed the master cylinder and fluid is coming out at all 4 brakes when I bleed them. I’m not sure if the ABS system has anything to do with not building pressure. I checked for leaks and don’t see any. I’m gonna replace the front brake hoses since they too look old to see if that makes a difference.

 

[TXd150]

Replaced front brake hoses and did a good brake bleeding, pleased to report truck is working fine now. Brakes stop on a dime and no more Brake / ABS lights on anymore. Thanks to everyone who gave advice and shared knowledge on this problem I was having. I can now get back to driving this truck to get it inspected and Tagged. The guy at the shop told me to drive it around a while before inspecting it, drove about 60 miles and took it back to inspection shop. He said it needed more time on the road, cat converter and evap showed “ not ready” whatever that means. I’m gonna try again

 

[Mojo88]

If you use a scanner to clear trouble codes, it resets all the monitors. Then you need a "drive cycle" or more, where those monitors go through all the self-diagnostics, and eventually (hopefully) they all reset back to "READY".
The EVAP monitor usually takes the longest to reset.

Glad to hear you got the brakes fixed.......

 

[TXd150]

Thanks for explaining this to me.