Hard brakes

[92Ty#1524]

History: About 4 years ago, I had a brief moment of illiteracy and mistook the bottle of STP power steering fluid for STP brake fluid. (they look the same at a glance). It took about and hour for it to ¨melt¨the rubber diaphram under the mastercylinder cover. After I figured out what I had done I removed the ABS, bled the hell out of the system, new master cylinder, new calipers and cylinders. The truck has never been right since. I put another master cylinder and calipers on last year because the fluid was turning black and the brakes were getting hard again. I figured some residual ps fluid was still in there eating up seals. It didnt quite get them back to the original feel.

Last week: Flushed the system, new booster and master cylinder, SSBC calipers, new cylinders.

The pedal goes about half way down. Solid. Feels like the booster isnt working. Doesnt stop worth a crap and cant hold the truck for a boost-up. Same ol thing with brand new parts. The only thing original is the proportioning valve. Any chance that can be an issue?

I´ve searched this site and many others for brake troubleshooting. They all say the same thing for diagnosing system components. Not one of them makes mention of what to do when a jackass puts ps fluid in the brakes.

Any ideas????

 

[crawlinGT]

Re: Hard brakes

did you replace the lines also?

 

[92Ty#1524]

Re: Hard brakes

Um, no. What are they lined with on the inside? I assumed that since I was getting fluid out when I bled the fronts that it wasnt an issue.

 

[QUICK STORM]

Re: Hard brakes

replace the proportioning valve, then see whats going on. flush the abs unit as well.

also, is your engine making good vacuum?

 

[92Ty#1524]

Re: Hard brakes

The engine makes excellent vac. Is about 19" at idle. ABS has been gone for several years. The proportioning valve and front flex lines are the only things that havent been replaced.

 

[HotRodV6]

Re: Hard brakes

yeah i would replace the prop valve just becasue its all that is left that is stock, and then bleed the system real well. Also if you havent done so already, replace the flexible rubber lines with braided stainless lines.

I wouldnt think youd have to replace the hard lines, as far as i know they are not coated at all so nothing to come out, but maybe due to age there is internal corosion??

Might be a good excuse to order a complete set of stainless hard lines from inline tube for about 200 bucks, and all the flex lines with braided stainless hoses.

Good luck

 

[92Ty#1524]

Re: Hard brakes

I was going to replace my flex lines with braided but couldnt find em.

Are there any rubber components in the prop valve? I´m gonna replace it regardless. Just curious.

 

[HotRodV6]

Re: Hard brakes

not sure if there is or not, never had one apart.

 

[QUICK STORM]

Re: Hard brakes

i think there might be some type of bushing in the valve. maybe it swelled up as well.

 

[Ron 92ty]

Re: Hard brakes

there is rubber peices in the prop valve. replace it and it will be fine

 

[Daryl H]

Re: Hard brakes

lmctruck.com has stainless hoses, and replace the flex line on the rear diff and the prop valve. Not worth the money and time NOT to replace them. Dont find yourself caught up under someone elses bumper or in a ditch somewhere because you were saving 45 bucks.

 

[MR_MNZTR_SY]

Re: Hard brakes

i would double check that the master cylinder is correctly installed in the booster. i once knocked the rod off the booster while installing a master cylinder.. just gotta kinda take it all apart and put it all back together again.