coolrotariesR1

iTrader: (2)

Hey y'all. Question for the FD gurus.. I have a 93 that sat for years and now that I have it back from the shop I'm told that the reason for the lack of brake pressure and the clutch engagement being high is that the master brake is compromised and not holding pressure. They tried bleeding the system but none of the fuild was coming out.

Now there are no signs of leakage from the reservoir so my question is would the solution be to rebuild the Master or just install a 626 Master.
Thanks!

apexhittinbull

iTrader: (21)

Hey Texmax,

You're going to have to transfer either 929 reservoir to FD one, or the other way around along with bending couple new hard lines.
Either way new o rings and seals are required.
Overkill solution would be to have a separate reservoir between the brake and the clutch, which I have not looked into yet.
Reseal kits are fairly cheap for either master or a slave.
Make sure to check for leaks giving high brake pedal pressure after the install.

nmoffatt

iTrader: (15)

I had exactly the same issue. Picked up both rebuild kits from Mazda. It was pretty straight forward. It would also be a good time to upgrade to SS brake lines

cr-rex

iTrader: (114)

For starters..... the brake master failing has no influence on the clutch. The clutch has its own master and only shares a reservoir with the brake master. In the fact, the part of the reservoir the clutch uses is partially blocked so even if you lost all the brake fluid through your brakes, the clutch will continue working since there is a wall INSIDE the reservoir that keeps them separate. So they're definitely wrong on that. The clutch engagement can be tuned somewhat by adjusting the rod at the top of the pedal. It mostly depends on the clutch itself. They're all different.

As far as the lack of brake pressure or poor brake performance, it may not necessarily be that the master is bad although it certainly is possible. It could simply be they are bleeding it wrong or there is something else. Cars that sit for extended periods like yours can get some funky issues with the brakes that can clear themselves up simply by driving.

Of course if its the original master then there's nothing to lose by replacing it anyway. It will only help. I would advise keeping the stock master and rebuilding it or replacing it. Changing to the 929 master without cause is pointless.

Sgtblue

iTrader: (16)

I don’t follow. Why is overcomplicating things by changing to a component from another model being considered? Why not just rebuild it or replace it? The reservoir itself might not be, but I think master cylinder is still available. At any rate I agree with cr-rex…it’s two different issues.
The clutch engagement point might just be an adjustment issue, something related to sitting or maybe even a badly worn disc. New clutch master and clutch slaves are relatively cheap and easy especially if dis-engagement is the issue.

DaleClark

iTrader: (55)

First off, If you have a car that has sat for years there's no way the hydraulics are healthy. Get all new hydraulics across the board. Even if you can get them to work you'll probably have issues in short order.

That said, the clutch pedal should have about an inch or so of slop at the top of the pedal stroke then you can feel the pressure all the way to the floor. If it is like that, the clutch hydraulics are working as advertised. If the engagement point on the clutch is really high you probably have a super worn clutch disc. As they wear out the engagement point gets higher and higher then starts slipping as the disc gets thinner.

You'll have to define "lack of brake pressure".

Also the 929 master cylinder is the one that is commonly used. I'd try to get a good regular stock master first, the 929 requires more work and a little fab to install and you won't really gain anything by going to the larger bore master on a stock brake setup.

Dale

coolrotariesR1

iTrader: (2)

Thanks all.
The clutch is a new and is a stage 3 excedy.
When pressing the brake pedal it literally goes all the way down and I can't stop. I have to use the brake handle to stop.
It seems like sticking with the factory master is the way to go with a new rebuild kit but is it difficult to remove without spilling fuild everywhere?
I forgot to ask if it could be the brake booster also.

Sgtblue

iTrader: (16)

Changing or rebuilding the brake master cylinder might fix your brakes, but understand that unless the shop is simply not keeping up the fluid level in the bulkhead section of the reservoir devoted to the clutch, it probably won’t do anything for your clutch issue. Clutch hydraulics are done by the clutch master and clutch slave.

DaleClark

iTrader: (55)

With a heavier pressure plate you will HAVE to have a stainless braided line going to the clutch slave cylinder. The stock rubber line will flex too much resulting in engagement that is down at the floor or not fully disengaging.

As stated, you will want all new hydraulics. Especially the clutch master and slave. You will be putting a heavier than stock load on them and the old parts can't cut it.

Not sure why this is a mystery to the shop, this is plain vanilla as far as brakes and clutch hydraulics are concerned. It's the same as any other car. The FD doesn't do anything weird except maybe having a shared reservoir.

Dale

coolrotariesR1

iTrader: (2)

Thanks Dale. Unfortunately I have my opinions on the shop....
So with a heavier pressure plate and the stock clutch line I am to expect the high engagement as well? Or are we still looking at the clutch master and master brake as the culprit?

Sgtblue

iTrader: (16)

If the stock clutch line is ballooning I’m thinking low pedal engagement, and/or incomplete disengagement.

DaleClark

iTrader: (55)

We may need to define the engagement point.

At rest the clutch pedal is at the top of its travel, you push it down to the floor and it's at the bottom of its travel.

A heavy pressure plate and stock clutch line will result in the engagement point being at the bottom of the clutch travel, by the floor. That's because the hydraulic pressure to make the clutch move is being used to swell the stock line like a balloon. Stainless line fixes that in a jiffy.

If the clutch engagement point is all the way at the top of the pedal travel just before it's at the rest point something is wrong. That gets complicated.

Dale

coolrotariesR1

iTrader: (2)

Yes Dale, the engagement (starts to grab) is at the top of the pedel travel.

DaleClark

iTrader: (55)

That is WEIRD. Typically the only way that happens is if the clutch is super worn out and you have a brand new one.

So, when you go to drive, you barely have to push down the pedal and the clutch disengages/you can shift gears/the car coasts?

Does the whole rest of the clutch pedal travel feel normal?

I'm wondering if they botched the clutch install somehow like putting the clutch disc in backwards. That's not a hydraulic issue.

Dale

coolrotariesR1

iTrader: (2)

Thanks Dale. I'll have to explore this further on my own as the shop that did the work is out of state. Very frustrating.... This why shops get a bad reputation...

nashman69g

iTrader: (3)

One other possibility is the push rod could be adjusted to far in.

coolrotariesR1

iTrader: (2)

Thanks Nashman69g. I'll give it a try.

coolrotariesR1

iTrader: (2)

Just a quick update. I rebuilt the master brake and master clutch, now have normal pedal pressure.

Sgtblue

iTrader: (16)

It might be time for a new clutch slave (and maybe a stainless line) if it was sitting that long and the clutch master was bad. Neither is terribly expensive or hard to replace. Just a thought.

coolrotariesR1

iTrader: (2)

I did install a ss braided clutch line. I also bled the clutch but still feel that there is air in the line. I'm using a suction tool that pulls the fluid out without pumping the clutch or the brakes. I see the bubbles coming out but still a lot.

DaleClark

iTrader: (55)

With a Mityvac-type suction tool you will always see bubbles. It's drawing air around the threads of the bleed screw. If the pedal feels good and the clutch engagement point is in the middle of the pedal travel you are good.

Dale

coolrotariesR1

iTrader: (2)

Dale this is what I used. Not sure if the same as you mentioned. The brake pedal feels better but I feel that it can still be firmer. As for the clutch pedal, it's still engaging up high. My next step is changing the salve cylinder which is on order from Mazda. After that if still the same I throw my hands up with frustration 😜

DaleClark

iTrader: (55)

OK yeah you will always see bubbles with that.

As stated before, high engagement point is either a worn clutch or a really mis-adjusted clutch pedal. Or a clutch installed backwards or something super weird like that.

Getting a hard brake pedal is EXTREMELY difficult, don't go overboard chasing that rainbow. Like you need new EVERYTHING and a miracle to pull that off.

Dale

coolrotariesR1

iTrader: (2)

Dale, question for the guru. Its been ages since I last drove the FD and I notice that it take a bit of effort to get the gas pedal going. So it goes like effort on the pedal then response. Is the sticking point coming from the throtle body or the pedal?

DaleClark

iTrader: (55)

It's either the TB or the cable. Bad cables are pretty common.

The pedal itself I doubt would be the issue, they flop around easy without the throttle cable attached.

Dale