I have a 92 thor pinnacle 454 engine.I have a brake light lit up on the instrument panel.I went to check the fluid but couldnt find the master cylinder anywhere.I ran the lines from the caliber to the master cylinder and found it.If anyone is familiar with this vehicle and know what i am talking about how do you get to the master cylinder to check the fluid?I can see it from under the vehicle but i wouldnt be able to see the fluid even if i got it open.

My '84 Tasca had a cutout in the floor under the carpet.Otherwise, you take the LF wheel off.

Eversince the light came on seems harder to stop.Could it be the fluid being low or something else?Before hand always felt a little spongy but now more so.Almost scary.If i pump them they will get better.

That light will come on if the pressure in the part of the cylinder that operates the front brakes is different from the part that operates the rear. So, if fluid has gotten so low that one part isn't applying and the other IS, then the light will come on.I've seen this happen on vehicles and it's usually time for another master cylinder. One part is working and the other is leaking internally.

Access to my master cylinder is through the left front wheel well. I have hydraulic jacks that when fully extended makes it easier to go over the top of the wheel.The light could be on because of a problem with the auto-park if equipped on your rig. My light is on when rig is in park, and then goes off when in neutral or a drive position.

As J-D said, an imbalance in the hydraulic system, either from low fluid which can be caused by disc pad wear, or an internal leak will cause the brake warning light to come on. If you find tha fluid is low, be sure to find the cause, don't just add fluid and be done. If the fluid isn't low, it's probably an internal leak, and the master cylinder needs to be replaced. JMHO

master cylinder | Good Sam Community

MEXICOWANDERER
Explorer
Aug 29, 2015
23-years. Wonder when the last master cylinder replacement occurred? Or wheel cylinders? Brake hose inspection?
riggsp
Explorer
Aug 29, 2015
As J-D said, an imbalance in the hydraulic system, either from low fluid which can be caused by disc pad wear, or an internal leak will cause the brake warning light to come on. If you find tha fluid is low, be sure to find the cause, don't just add fluid and be done. If the fluid isn't low, it's probably an internal leak, and the master cylinder needs to be replaced. JMHO
enblethen
Nomad
Aug 29, 2015
Access to my master cylinder is through the left front wheel well. I have hydraulic jacks that when fully extended makes it easier to go over the top of the wheel.
The light could be on because of a problem with the auto-park if equipped on your rig. My light is on when rig is in park, and then goes off when in neutral or a drive position.
j-d
Explorer II
Aug 29, 2015
That light will come on if the pressure in the part of the cylinder that operates the front brakes is different from the part that operates the rear. So, if fluid has gotten so low that one part isn't applying and the other IS, then the light will come on.
I've seen this happen on vehicles and it's usually time for another master cylinder. One part is working and the other is leaking internally.
joe0508
Explorer
Aug 29, 2015
Eversince the light came on seems harder to stop.Could it be the fluid being low or something else?Before hand always felt a little spongy but now more so.Almost scary.If i pump them they will get better.
RJsfishin
Explorer
Aug 29, 2015
My '84 Tasca had a cutout in the floor under the carpet.
Otherwise, you take the LF wheel off.

Forum Discussion

master cylinder

About Technical Issues

Related Content

Master Brake Cylinder

F53 brake master cylinder failure

Master Cylinder??

Wrong Brake Master Cylinder

Master cylinder