Hotwheelbill

My brake problem is getting worse. It only happens when coming to a stop and not all the time, but most of the time now. As I come to a stop and even up to 5 mph, when I apply the brakes the peddle drops an inch or so and I loose the front brakes. My first thought would be the Hydraboost , but I do not fully understand how this thing works. Any ideas of where to start looking?

Also, the ABS light has been on as long as I have had the truck. July 09

nickg

try applying brakes and hold, if the pedal starts to sink to the floor then it would be either a leak (externally) or a faulty Master cyl.
if you loose brake assist then that would be a Hydro boost issue (if you loose assist it will feel like a hard to push pedal, same as if the engine is off and you have pumped the brakes a couple times, and it is hard to apply the brakes)

I'd suspect a leaking wheel cyl or faulty MC.

do you have 4 wheel ABS?

Hotwheelbill

No leaks. It may be just the loss of power assist. that I am feeling, but I have hit the brakes hard when this happens before and only locked up the rear wheels. Then again this was at a very slow speed. I don't know if it is 4w ABS or just rear wheel ABS.

Copenhagenjunkie

Believe its only rear wheel ABS.

Hodge

I have been working through brake problems on my 94. Mine has a seperate abs controller for the front wheels. You should check if yours does. It would have a rear abs valve under the master cylinder, and the front abs controller would be on the firewall. Perhaps there is an issue with the front controller, or the front wheel sensors. I had a hard pedal that was intermittent, and replacing the brake booster has taken care of that. That would not make your front brakes fade while the back ones held, though. That would have to be in the combination valve, abs controllers, or a leaking caliper.

RPegram

I second (could be third or fourth) that you have an ABS problem. I had a sensor on front wheel go bad and when I would mash brake pedal, rears would lock up and front do nothing. A bad sensor on front would definitely cause ABS light to come on. Check for codes and see what it tells you.

nickg

if only rear abs (look for wires comming from front hub/bearing assy) it can be a failed MC (1/2 that controls front brakes leaking internally),
if rear abs check sensor on rear diff and wiring up to where it dissapears into main harness near fuel tank, wiring known to break right where is goes into harness, wires might look good but broken inside plastic, run your thumbnail against the wire while pulling, if broke you will feel it.

if the pedal feels hard when you loose brakes then its a hydroboost issue, if it sinks after applying (still soft) then you have a leak or an internally leaking Master Cyl

dozer12216

Put a master cylinder on it and be done. The red brake waring lite is tell of pressure differential. Pedal goes down when leak in primary MC. Pedal gets hard when that piston bottoms out and only have rear brakes.
Make sure rear brakes properlly adjusted also.

Hotwheelbill

Well here is the update. Even though I have a print out of the last brake jop by the PO, the fluid is a cloudy tea color....(southern tea...dark!). I am planning of a flush and while I am at that I will do the rear cylinder Chevy upgrade.
Also, I found some Syn. Power Steering Fluid at Pepboys.....$9.99 for 12oz. I went ahead and bought 2 bottles and pulled out 15oz of the Syn. ATF that I had used to flush the power steering pump with last month. Replaced with 12 oz of Syn power steering fluid and I will do the same next week with the other 12oz bottle. Mean time I will order some RP fluid. It may have helped a little, but after 3 hours of in and out running some errands, it started doing it again, but just a little in the last 4-5 feet of stopping.

I will look at the other items after I get these two things done (they need to be addressed anyway). Thanks for the info and advice.

Hotwheelbill

Well I had the Master Cylinder replaced and fluid flushed on Monday and the brakes at still doing the same thing and now more!! The front brakes are dragging and peddle was rock hard. It was bad for a while with the brakes smoking when I stopped and let them cool...45 min, and continued down the road they were better but still a very light drag. Left side seemed hotter than the right side.

1) Could I have gotten a bad Master from RockAuto?
2) Could both calipers go bad at the same time?
3) Could the caliper pistons have been pushed in without cleaning them off when the reinstalled them and causing the problem? (Always had good service at this place)
4) Could the HydraBoost cause all of my listed problems from the start?

dkenny

how about the condition of the flexible brake lines near each wheel?
have these been changed..they might look good on the outside but falling apart on the inside..cause the front calipers to lock up..new master that's now working. and new fluid..

if the fronts lock again..open the brake bleed..it they release..its your lines or the 'new' master cylinder not releasing under pressure.

-dkenny

Hotwheelbill

I got two new calipers and lines from Napa yesterday as well as pads (mine got very hot). Plan on changing them after work, but I am thinking it may be the Master because of the rock hard peddle. I still have the old one that is still good because I still also have the other problem that I will change my rear ABS sensor to try and solve after this problem.

I need a Ford to put this Motor into!