Mechanics

QUESTION BRAKE PEDAL PUSHES ALMOST ALL THE

1998 Isuzu Rodeo

Brakes problem
1998 Isuzu Rodeo Question 6 cyl Front Wheel Drive Automatic 205K miles

Brought my 1998 Rodeo to the Isuzu dealership about 2 weeks ago because the brake pedal when you apply pressure moved almost to the floor. Was told initially that it needed a new brake booster. Told them OK replace. Truck won't be ready till the next day because they needed parts. Got called next day and was told that they found that the master cylinder had a " small leak" when they bled the fluids out and that would need replacing. Sd OK, go ahead. When I picked the truck up was told I would see a big difference in how the brakes/pedal felt. Boy I sure did! When I touched the brake pedal I thought I would go through the windshield. Drove truck home no problems. Next day took it out. After driving few miles I was having difficulty getting truck to drive forward when I pushed on the gas pedal. Truck just about stopped when I let up on the gas. Called the dealership back while I was driving was told to bring truck back in. Told them no way goiing to make it. I would have it towed. Went right home and by the time I got there I had smoke coming from under the truck, wheels/rims burning hot to touch. Had towed to dealership. Got call from them saying that because master cyclinder wasn't working properly for awhile that my rear brakes were not being used to their full extent. Rust got in there and because the master cyclinder is now working properly the rust is being pushed through and causing the brakes to freeze up. I would need new rear brakes. They said I have about 2-3mm left on the pads. They said they checked the front brakes and they are OK. They were able to free up the brakes and it was OK to drive but I should not wait past my next oil change. They said they noticed the rust when they worked on my truck but did not mention to me-forgot. I called two mechanics who both said they think they did not adjust the free play after replacing the master cyclinder. They wonder if I even needed the brake booster replaced. The dealership told me you can't adjust free play with disc brakes. Now the brake pedal is acting like it did before I brought it in to have it fixed 2 weeks ago. Any idea what may be going on? I was told by the dealership that it isn't fair to ask opinions of other mechanics when they were not the ones who were working on the car to see exactly what was going on. Opinion? Thanks
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LAEllis
October 5, 2008.



They are correct when they say you can't adjust free play on disc brakes. If the brakes were smoking, something was stuck. Did they replace rear calipers? Also, is there a chance that the E-Brake may have stuck? As far as the master cylender, it could cause a low pedal, but the booster shouldn't. Was the smoke coming from both rear brakes?

Let me know.

Joe

Hi Joe,

Thanks Joe for your quick response.

I did not have them replace the rear brakes. I was too angry. All they did was free up the brakes so it could be driven. I still haven; t replaced the rear brakes because they said I still had more time with 2-3mm left on the brake pads. The truck hasn't been driven much since I got it back- maybe 3-4x. But it will be driven alot now because my son will be using it. He drove it home yesterday and felt that I did that the brake pedal feels just like it did before I brought it to the dealership. I am not sure if smoke was coming from both rear brakes but definately from the passenger side as well as the front passenger side. When the tow truck driver came to my house( within 10 minutes of me calling) he asked me when I last drove the truck because all 4 wheels plus rims would burn someone to the touch) plus he said the caliper on the passenger front was blue. When I told dealership about the blue caliper their response was it can be blue anyway from heavy breaking and not just from heat. They said front brakes OK- no warping.

Tiny
LAEllis
Oct 6, 2008.
It is common for brakes to get hot; however, not as hot as you described, and they shouldn't smoke. At this point, I'm not sure what to tell you. I would have them check the e-brake for the rear brakes. As far as the front, I wonder if it could be caused by a bad rubber brake hose. After some years / miles, some rubber hose breaks down and allows fluid to go in one direction and not the other (which causes the brakes to stuck). At this point I would have to suggest for you to give them another try. Plus, they have to fix it. Keep in mind, if you don't like the car at this point, they only get three chances to repair a problem like this. It can be dangerous for the " driver to run the vehicle. If they don't fix it in three, I would fight it inder the lemon law and force them to take the vehicle back.

Good Luck,
Joe

Hi Joe.

Brought my 1998 Rodeo back to the dealership as you had suggested and they cannot find the reason why my brake pedal still goes to the floor. If you pump the brake will come back up. They said they tested the new brake booster and master cyclinder they put on it. Did a gravity bleed on it. Both test fine. They are perplexed. Said it wasn't a hose problem. Couldbn't find a leak or blockage. Have no idea. Said they had a another customer recently with same problem- different technician worked on vehicle. That customer is driving their rodeo and just being careful when braking. For me, it seems too dangerous now that winter is approaching. Any ideas?

Thanks.

Tiny
LAEllis
Oct 14, 2008.
Hi: If they checked everything and it's good, then the brakes should work properly. If the pedal goes to the floor, I would not drive it until it's repaired. By any chance is there an Isuzu dealer near you? If so, I would ask them to diagnose the problem and determine the problem. If they can fix it, I would try to have the place it's at now pay for it. If they are giving you a warranty and can't fix the problem, they need to find someone who can.

Let me know how it goes for you. I'm anxious to hear what the real problem is.
Joe

Hi Joe.

I spoke with the dealership again yesterday. They still have my truck. I spoke with another technician who suggested the problem may be a malfunction with the anti-lock brake system- specifically the electronic part of it. The dealership told me they had been focusing solely on the hydraulic part of the system. I emailed them the repair manual that the other technician emailed to me on how to check this problem.

I am hoping this is the answer. Will let you know. The dealership is anxious to check out this possibility. Will try to work on my truck today.

Thanks for replying. I will let you know the outcome.

Tiny
LAEllis
Oct 16, 2008.
I gaurantee that frreplay at the pedal WAS adjusted this way, But you have a leak somewhere in the system, with 205,000 mile, your calipers need inspection for fluid passing by the seals.
DISC & DRUM -1998 Isuzu Rodeo S
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NOTE: Brake pedal adjustment information for Hombre is not available.
NOTE: Push rod serves as brake pedal stopper when brake pedal is fully released. Pedal free play is measured with engine off, and brake pedal depressed 5 times to release power brake unit power assist.
BRAKE PEDAL HEIGHT, FREE PLAY & STOPLIGHT SWITCH
1.Ensure brake pedal is fully returned by pedal return spring. Start engine and rev several times to charge vacuum booster. Measure pedal height from upper foot rest portion of pedal pad to floor board. See Fig. 1 . Adjust pedal height to specification. See PEDAL HEIGHT SPECIFICATIONS table. 2.To adjust pedal height, unplug stoplight switch harness connector. Loosen stoplight switch lock nut to ensure brake pedal is fully returned. Loosen push rod lock nut. Rotate push rod to obtain specified pedal height. Tighten push rod lock nut to 15 ft. lbs. (20 N.m). 3.Turn engine off. Depress brake pedal firmly at least 5 times to discharge vacuum booster. Check pedal free play. See Fig. 1 . Ensure free play is within specifications. See PEDAL FREE PLAY SPECIFICATIONS table. If free play is not within specifications, repeat steps 1) and 2). 4.Check depressed pedal height. See Fig. 1 . With at least 110 lbs. (50 kg) stepping force applied to brake pedal, depressed pedal height should be as specified. See DEPRESSED PEDAL HEIGHT SPECIFICATIONS table. If depressed pedal height is not as specified, repeat steps 1) and 2). 5.After brake pedal height, free play and depressed height are to specification, install and adjust stoplight switch clearance "A" between stoplight switch housing (not actuating pin) and brake pedal tab to .020-.039" (.5-1.0 mm). See Fig. 1 . Tighten stoplight switch lock nut. Reconnect stoplight switch harness connector.
PEDAL HEIGHT SPECIFICATIONS
Application Amigo & Rodeo Hombre Trooper
In. (mm) 6.9-7.2 (174-184)
(1) 8.2-8.6 (208-218)
(1) Information is not available.
PEDAL FREE PLAY SPECIFICATIONS
Application Amigo, Rodeo & Trooper Hombre
In. (mm) .2-.4 (6-10)
(1)
(1) Information is not available.
DEPRESSED PEDAL HEIGHT SPECIFICATIONS
Application Amigo & Rodeo Hombre Trooper
In. (mm) 3.7 (95) 1.7 (42) 3.9 (100)
Fig. 1: Adjusting Brake Pedal Height & Free Play (Typical)
Courtesy of ISUZU MOTOR CO.

10/18/2008


http://www.2carpros.com/forum/automotive_pictures/62217_Freeplay_1.jpg


I believe the dealer adjusted too high and caused the brakes to drag....

Merlin2021
Oct 18, 2008.
Hi Joe,

The dealership checked the ECHU harness and said that wasn't it as another technician I spoke to suggested we check. As far as free play goes, I have disc brakes and I guess you can't adjust free play with disc brakes only drum. The dealership did say that they tried to adjust the brake pedal but when they do it puts too much drag on the brakes. I asked them if all the calipers checked out OKAY.
Reason being is because I had to have the truck towed to them the day they replaced the master cyclinder and brake booster because rear brakes locked up. I hear a loud bang from the back of my truck and their was smoke coming from rear. I asked if because of that if their could be a problem with the calipers and they told me no. I think the technician that has been trying to figure out the problem has been looking at the truck for too long and is missing something. My husband is going to take the truck elswhere for another opinion. Just to let you know they retested the new master cylinder and brake booster and they both check fine. Any other suggestions, please let me know. If we ever find the problem I will let you know.

Thanks

Tiny
LAEllis
Oct 19, 2008.
Did you read my post? Pedal freeplay is adjusted by adjusting the pushrod, if done wrong SEVERE brake drag WILL occur! This is true for disc and drum brakes!

Merlin2021
Oct 19, 2008.
Hi Joe,

I am sorry. I did not see the last line you wrote after you sent the instructions about adjusting the pushrod. I will assume then that the technician may have adjusted the pushrod too much initially and thats why when I stepped on the brake pedal it felt like I was going to go through the windshield? Would that be the reason the brakes locked up? They said it was because rust got into the brakes because the master cylinder wasn't working properly and the rear brakes were not operating at full efficiiency. When it was replaced and working properly the brakes were now working properly and it pushed rust into the brakes causing the pads and rotors to stick together. When he freed the rear brakes, the pedal was soft like it was before. They did say when I picked the truck up the other day that they did try to adjust the pedal and if they adjust too much it put drag on the rear brakes. When my husband drove the truck home from the dealer he said he could tell the pedal was adjusted but still had the problem of the pedal soft to floor.

Tiny
LAEllis
Oct 19, 2008.
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