Brake pedal goes to the floor

Tiny
EVILMINION
  • MEMBER
  • 1995 FORD RANGER
  • 2.3L
  • 4 CYL
  • 2WD
  • MANUAL
  • 305 MILES
So this is a long one. I have been working on my truck for six days now. The problem? Rear end went out. I own a parts truck so I just pulled every thing from that to put fix my running truck. Make sense. Except now I have no brakes. I have replaced: master cylinder, brake booster, and both rear wheel cylinders. Bled the mater cylinder and rear wheel cylinders. Then went back and bleed everything including the rear ABS. Still have no pressure when the truck is running. It does however build pressure when the truck is off. I am at a loss as to why I have no brakes just from changing out my rear end. If anyone can help please do. Also, if I take the vacuum line and cover it with my hand my brake pedal stiffens right up.
Do you
have the same problem?
Yes
No
Thursday, May 18th, 2017 AT 10:01 PM

7 Replies

Tiny
CARADIODOC
  • EXPERT
Was that a used master cylinder you installed? Did you pedal-bleed the system with a helper, and if so, was the brake pedal pushed all the way to the floor at any time?

The power booster is not part of this problem and should not have been replaced. It simply makes the brake pedal easier to push when the engine is running.

Do you have brake fluid running out of the two rear bleeder screws?
Was this
answer
helpful?
Yes
No
Thursday, May 18th, 2017 AT 10:35 PM
Tiny
EVILMINION
  • MEMBER
No the master cylinder is new, yes I had help. As for the brake pedal being pushed to the floor I am not fully sure. There are no leaks at all.

If I block the vacuum line on the brake booster the pedal goes stiff. I have never had this issue. Now, I am thinking of pull the ABS fuse. Would that solve the problem?
Was this
answer
helpful?
Yes
No
Friday, May 19th, 2017 AT 7:46 AM
Tiny
CARADIODOC
  • EXPERT
Pulling the ABS fuse won't do anything. The system is at rest when no skid is being detected. The valves will be in the same states when the fuse is pulled or when the ignition switch is off. If you have four-wheel ABS, it may be necessary to use a scanner to command the computer to open two valves so the air trapped in two chambers can be expelled. If you have rear-wheel ABS, you treat that like there's nothing there. Fluid and air will go right through it.

The issue with pushing the brake pedal to the floor is crud and corrosion can build up in the lower halves of the bores where the pistons don't normally travel. Pushing the pedal over half way, whether surprised by a sudden leak, or when pedal-bleeding, runs the rubber lip seals over that crud and can rip them. That results in a slowly-sinking brake pedal or a failure to build any pedal pressure, and that often doesn't show up for two or three days. Since you installed a new or rebuilt master cylinder, you don't have to worry about that. The crud becomes an issue when the master cylinder is more than about a year old.

The next thing to consider is if the truck is jacked up or on a hoist with the rear axle hanging down, you may not be getting enough fluid flow to push the air out. Most trucks and minivans have a height-sensing proportioning valve at the rear axle because there can be such a wide range of loading on the rear. The hanging axle will make it look like the rear is lightly loaded, so fluid flow to the rear will be reduced. Also observe if the brake fluid coming out of the bleeder screws is dark or clear. If it's dark, there's still old fluid in the line, and it's likely that is where the trapped air is.
Was this
answer
helpful?
Yes
No
Friday, May 19th, 2017 AT 8:56 PM
Tiny
EVILMINION
  • MEMBER
Thank you for help. I have fixed the issuse. One of the calipers went bad
Was this
answer
helpful?
Yes
No
Saturday, May 20th, 2017 AT 11:01 AM
Tiny
CARADIODOC
  • EXPERT
What was the cause of the problem? Was the caliper not sliding on its mount?
Was this
answer
helpful?
Yes
No
Saturday, May 20th, 2017 AT 5:37 PM
Tiny
EVILMINION
  • MEMBER
The top piston wasn't was completely in. But I do have another question. After putting on a 4 inch lift my steering is not lined up. How do I fix that? Or will an alignment fix the problem since I definitely need one now anyway?
Was this
answer
helpful?
Yes
No
Sunday, May 21st, 2017 AT 11:29 AM
Tiny
CARADIODOC
  • EXPERT
AUUUGGHHH! I'm a suspension and alignment specialist, and as such, I never get involved with raised trucks or lowered cars. Correct ride height is critical to best handling, braking, steering response, comfort, and tire wear. When I worked at the dealership, I had the owner's blessings to refuse to work on any altered vehicle because doing so could make us party to a lawsuit, even when what I worked on had nothing to do with the suspension system. This is also serious enough that members of my school's Advisory Committee, including my former boss / owner of the dealership, and the owner of the local Goodyear store, got wound up if I even allowed a student to bring a vehicle into the shop with altered ride height.

That said, and without going into my really long, detailed explanation of why this is such a big issue, you can't assume anything about the alignment, centered steering wheel, or tire wear. Ford is by far the worst manufacturer when it comes to tire wear problems, most of which can't be fixed. You just have to keep buying new tires. The Bronco 2 and the Ranger are two of the worst models Ford has for tire wear, other than the very dangerous '80s Ford-built Escorts and Tempos. What you have going for you is your truck is a two-wheel-drive. Look at any four-wheel-drive model when it's on a hoist and you'll see the front tires are tipped WAAAAAY out on top. There's no denying the twin I-beam suspension system is strong, but it is the worst possible system for tire wear. On those models, the wheels go though the same motions, tipping in and out on top, as the truck goes up and down on the road.

You should have the much-improved "short arm / long arm" front suspension system which includes the upper control arm and ball joint, and a lower control arm and ball joint. If you installed "drop spindles" to raise the truck, those do not alter the geometry of the front suspension system. Think of parking the truck with the tires sitting on top of 4" x 4" blocks of wood. The body is 4" higher off the ground, but the lower control arms are still perfectly parallel to the ground.

If you installed longer coil springs in the front, or, turned up the torsion bars, you will see the lower control arms are no longer parallel to the ground, and the upper control arms are drooping way down. That will make the wheels tip in on top, and the tires will wear out very quickly on their inner edges. No alignment will solve that because even if there is enough range of adjustment to get the numbers to be in specs on the alignment computer, those numbers only refer to a truck that's standing still. The suspension's geometry is deigned to minimize the angle changes each wheel goes through while the truck is in motion. That design is rendered ineffective at any ride height except what's specified.

To address your question about the steering wheel, I could explain it better if I was looking at your steering system with you there so I could point to things. I think you have what is called a "parallelogram" steering linkage. That will have an inner tie rod end, an outer tie rod end, and an adjuster sleeve connecting them, on the left side, then it will have an identical setup on the right side. There will be an idler arm on the passenger side, and a pitman arm on the driver's side. That system is more forgiving for tire wear, but those tie rod linkages need to be parallel to the ground. That can't happen when the lower control arms are angled down.

Ford also used a steering linkage with a link that runs from the pitman arm to the right spindle, then a shorter link is attached in the middle of that link on the right end, and to the left spindle on the other end. That system is practically designed to cause bad tire wear, but that is minimized when the truck is at the correct ride height. That proper ride height places both links nearly perfectly parallel to the ground. The problem is being many different lengths, no linkage or control arm goes through the same angle changes as the truck bounces up and down. That means the front tires turn left and right as the truck bounces up and down. That is minimized to the point the truck is driveable when it's at the specified ride height. At any other height, you're going to find it darts to one side when you hit bumps in the road. That's not a concern if this is a hunting or off-roading truck, but it will be very tiring if you try to drive it long distances at highway speed.

The concern right now is by raising the suspension, the outer ends of the steering links have pulled in, and if they're the unequal length links, they've pulled in unequal amounts. That turns the wheels an unequal amount. You have to bring them back, with the steering wheel, to where they're turned in or out equally for the truck to go straight, and that point is not the point the steering wheel is straight. That refers to "toe", which is the final adjustments made during the alignment. Toe is normally set to make the front wheels slightly closer together in the front so road forces pull them back while driving so they're perfectly parallel. That provides the best tire wear. Your mechanic may ask you how heavily-loaded you normally have the truck, then he might alter the toe adjustments to try to compensate for the bigger steering changes the wheels will go through.

Nothing will happen to the rear axle or rear suspension because they just go up and down. The only concern there is with the drive shaft and u-joints. There's a definite angle difference between the drive shaft and the transmission's tail housing, and between the drive shaft and the axle's pinion gear. That angle forces some rotational movement in the needle bearings as the drive shaft rotates. That is needed to prevent the needle bearings from constantly sitting and wearing in one spot. The concern is if that angle gets too big, a vibration can be set up, and that occurs at a specific range of speeds. This used to be a problem with older GM trucks and full-size vans, and was just the "nature of the beast".

Ford also had problems with that drive line vibration on conversion vans when they got to be about six months old. Many of their vehicles were tied down too tightly on the car haulers when they were delivered to the dealerships, and that stressed the springs and lowered ride height. That vibration showed up after a few more months, and was aggravated by the constant added weight of the conversion furniture.

I only mentioned all these things so you won't try to correct any problems while being unaware of the actual cause. The alignment won't solve everything, but you can expect the steering wheel to be straight.
Was this
answer
helpful?
Yes
No
Tuesday, May 23rd, 2017 AT 12:04 AM

Please login or register to post a reply.

Recommended Guides