Funky Hydraulics 2004 Mazda B2300

I have a manual 2004 Mazda B2300 (86k), transmission rebuilt and clutch replaced 2.5 years ago, with no problems until…

The hydraulics went out in the truck on Thanksgiving, I could press the clutch down with resistance but could not shift into any gear, I was stuck in neutral. The master cylinder was replaced and I could drive the truck for a bit but within a few miles the transmission would grind when I shifted, particularly in traffic situations. Since the intermittent grinding began I have taken the truck in 5 times to two different shops. The slave cylinder and the master cylinder have both been replaced several times to rule out bad parts. Considering the slave is internal this was expensive.

I keep being told that the transmission isn’t being bled right, that there is still air stuck in there. But alas, every time I bring it to have it bled again I get it back and there is still grinding and the clutch is almost to the floor when I shift. The shops are sick of me and not making this a priority because they are losing money. They don’t take me seriously and keep saying that ‘this is just how it is’. Two months later and I don’t know what the heck to do anymore.

Suggestions? And FYI I keep the car in good condition with regular tune ups and oil changes. I don’t commute and only drive it about 50 miles a week

I can’t imagine that they said the transmission wasn’t bled right - but perhaps the hydraulic clutch lines weren’t bled right. This is not “just how it is” - it’s on whichever shop did the master/slave to properly install the stuff and bleed the system. If you’ve used two shops and each has done different things (e.g. slave at one and master at another), then you are probably stuck - because each has the ability to say “not our problem, take it back to X”

What kind of shops are we talking about? Big-name, corporat “auto care” chain shops? Or local little “Bob’s car repair” shops? You need the latter.

Just a thought… Check for cracking on the firewall where the clutch pedal bolts to the firewall and meets the master cylinder. Years ago I had a co worker that had a truck with a hydraulic clutch and the firewall metal fatigued and cracked, when you would push the clutch pedal it wouldn’t always have a full range of motion and would result in incomplete clutch disengagement.

Im sure this is unlikely, and surely someone would have caught it by now, but it couldn’t hurt to look.

@WheresRick reminded me of a car I purchased 14 years ago. I picked it up from a car lot with a major discount because of a clutch problem noone could solve. It took me a couple of days, but I found the problem. It was a broken clutch adapter that a replacement cost me $25 at the dealer. The adapter had a crack that opened up under load, and only allowed the clutch to move halfway, never fully release.

Can’t really diagnose if there is air in the clutch lines via the internet, that has to be done by your mechanic. On my Corolla at least that is a fairly simple thing to do. It’s true if there is air remaining, this is the symptom you’d expect. Same if the clutch master or slave cylinders were defective. But as mentioned above, good idea to at least visually check all the clutch mechanical linkages, starting with the clutch pedal itself. Get a good flashlight and have a look-see. It could be some pedal adjustment gadget has just come loose. Or a spring has broken somewhere.

These trucks (Ford Ranger) are notoriously difficult to bleed out, and unless the shops you used have experience with these and pre-filled and bled the slave cylinder before installation there may still be air in the system.

Try this…sit in the truck and as fast as you possibly can pump the pedal 20 times in rapid succession. At the last pump hold the pedal to the floor for 10 seconds and then quickly “sidestep” the clutch pedal–let it return up with a bang. Repeat this 4 times, let the truck sit for 10 minutes and then see if you have a better pedal.

Also, as noted above check the firewall where the clutch master is bolted, also check the pedal assembly and “hanger” itself for wear and misalignent. I’ve seen trouble with the pedal too.

Thanks for the pointers everyone. I will do my best to determine if it is the firewall, I haven’t heard that suggestion yet.

@cigroller I am working with AAMCO (transmission specialist shop) who did the initial transmission rebuild 2.5 years ago. They felt bad that this problem started just after my warranty was up so they gave my 1/2 price on labor for the slave and master replacement. I had the master initially replaced by a mom and pop shop in Berkeley but it took them over a week to get it back to me when the master replacement was only a 1 hour job. Fearing I would never see my truck again I brought it to AAMCO, who has now been working on it intermittently for the last 5 weeks… ugh.

Considering that the grinding only occurs after the truck has been driven for a few miles can I rule out a transmission problem? Does everyone agree that this is in fact a hydraulic issue? I should preface this with, upon turning the truck on the clutch is sticky, then shifts smoothly for a few miles, then grinds and looses power (is to the floor but never completely goes out)


Not possible to rule out either the transmission or clutch internals without removing them for a look-see. You could have a broken spring in the clutch for example. Still, I think it is more economical to make sure it isn’t a simple hydraulics or linkage problem before resorting to removing the transmission.

FYI, AAMCO is not generally considered to be a good shop to take a car to.

Is there any excessive free-play in the clutch pedal before you can feel any fluid pressure?

@ok4450 yes lots of free play (if I am interpreting that right: no pressure in the clutch until it is 50% pushed down. Before it was about 25%.)

@shadowfax, I realize that now :frowning:

@georgrSanJose, I am beginning to think it might be transmission, after having the slave and master replaced twice and having it bled 4x.

I have also heard a theory that there maybe some metal in the transmission that moves around and causes grinding after the truck is heated up, perhaps that is why it only occurs after driving it for awhile?

Right now it is in front of my house until my cousin’s friend who owns a shop can take a look at it. Seems the truck has a bad problem that is only remedied by 1) trial and error through replacing master and slave cylinders or 2) taking the entire transmission apart for diagnosis. So I am out a ton of money either way. Bluebook says the value is ~3k if brought to a dealer or ~5k if sold privately (granted it runs well). I may just have to walk away.

Sounds to me like way too much free play between the pedal and the master cylinder.
I looked at a picture of the master cylinder on and it appears there’s an adjustable push rod to set the free play.
Just throwing a new master cylinder on doesn’t help (as you’ve found).
I think you just need to find a mechanic who knows how to set it up properly.

Update, the truck is now grinding going into 2nd, 3rd, and 4th 100% of the time and with great difficulty. Now the diagnosis is bad syncros. Taking the transmission apart this week. They are not charging me for labor, thank god. Will update the post when/if this issue is ever resolved. Thanks again to everyone who contributed to this discussion! Wish me luck!

It sounds like you clutch is dragging, not necessarily due to a hydraulic failure. Sometimes the pressure plate won’t completely release because of a broke or weak release finger on the diaphram spring.

When idling in first gear with the clutch pedal depressed will the truck remain stationary or does it keep pulling?

I agree with the person that stated it wasn’t bled correctly. Those trucks (ford) are a bugger to bleed all of the air out. You need to use a vacuum pump. The step on the petal, bleed, repeat does not work. Unfortunately it sounds like you’ve torn up the syncs in the tranny now.

So, I got the truck back two weeks ago and the mechanic said is was the bushing pilot all along!

Not that it matters anymore, I was driving on Highway 17 near Santa Cruz last weekend during a downpour, hydroplaned, rolled, and totaled the truck. Luckily no one was hurt and no other vehicles were involved. In my defense I was being a cautious driver, was going under the speed limit and gave myself lots of space between other drivers given the conditions. This is my first accident in 12 years of driving.

I had the tires and shocks checked last summer because I had been having issues with fishtailing in wet conditions and they told me everything was fine. Needless to say, this truck committed suicide and won’t be giving me problems anymore.

Thank God noone was hurt. Thank you for the update. Glad to hear you are Ok.

For future reference, the fishtailing when wet was your indication of a problem. I would also mention that if you hydroplane - then whether under the speed limit or not you were going too fast for the conditions - given your tires. I have no idea what anyone did to “check” your tires. But regardless of tread depth not all tires are created equal. You needed better tires and slower speed.

I know this stunk for you and I’m also glad no one was hurt. So it’s not a “lecture” or something. It’s FYI. Your tires were obviously a problem - and anytime they aren’t firmly on the road, you’re going to fast regardless of anything else.

I’ve had bad wet weather tires before. There’s no way to tell just going to a tire place. I now use online reviews at sites like TireRack when I need to get new tires and one of the things I am paying a lot of attention to in those reviews is wet weather traction / hydroplane resistance. So add such a routine to your tire shopping.

The unusual weather here could have contributed too. Santa Cruz is in the San Jose area. We’ve had very unusual winter weather, very little rain at all. Maybe one rainstorm in December, and I don’t think it rained once in January. We’re only at 15% of normal rainfall to date, big drought. Then recently we’ve had some rains. With no rain for months the road accumulates oils on the road surface which don’t get washed away, then when it does rain it makes the roads super slick. With a few days of rain the roads return to normal, but during the transition from dry to wet they can get really slick.