R34 Gt Master cylinder replacement

[skylinebey]

Hello,

I have a R34 GT and my brake pedal has no pressure. I have replaced my master cylinder with a used one from Ebay and same result. When I pump the brakes it hold pressure for a few seconds with car on.

I can only find refurbished parts, is there a way I can use new brake master cylinder from another vehicle?

Edited April 2, 2020 by skylinebey

[KiwiRS4T]

If you take your M/C to a brake specialist they should be able to repair it with new seals. If it is badly worn and pitted they can resleeve it. If you can find a new one it is likely to be up around $400 -$500.

Have you checked out the supplier below? They have a couple of items they say will fit the R34.

https://www.ebay.com.au/itm/OEM-QUALITY-Brake-Master-Cylinder-For-NISSAN-280ZX-S130-Part-JB1362/172450975591?fits=Plat_Gen%3AR34|Make%3ANissan&hash=item2826e10f67:g:KmcAAO

Or try Amayama...I have previously bought an R33 M/C from Nissan in NZ but I believe most Aussie dealers will not get one for you. 

[skylinebey]

Thanks,

This is my second refurbished MC from eBay and same result. 

I tried the mechanics here and they don't have any repair kits.

So I will have to look on eBay for a resLeeve kit.

Does the brake booster go bad?

If so, how to I check ?

Thanks again

[KiwiRS4T]

13 minutes ago, skylinebey said:

Thanks,

This is my second refurbished MC from eBay and same result. 

I tried the mechanics here and they don't have any repair kits.

So I will have to look on eBay for a resLeeve kit.

Does the brake booster go bad?

If so, how to I check ?

Thanks again

The one I listed is supposed to be brand new, not refurbished. Your average workshop will not do the work -  you need a brake specialist. You will  not likely find a kit on Ebay.

Brake boosters can fail but you would have the opposite problem - a lack of assistance, not the pedal sinking to the floor.

Have you checked each corner of the car for leaking brake fluid?

[GTSBoy]

4 minutes ago, skylinebey said:

This is my second refurbished MC from eBay and same result.

Don't buy "refurbished" MCs from eBay.

5 minutes ago, skylinebey said:

I tried the mechanics here and they don't have any repair kits.

So I will have to look on eBay for a resLeeve kit.

You don't want a kit. You don't want a mechanic. You want a brake specialist, exactly as Kiwi said. You take YOUR MC in there and they fix it, and they give you a warranty. If you take it home and install it and the pedal is still f**ked, it is very much more likely that you've got another problem, not that the MC is still faulty. And then you start to think about your caliper seals, etc.

7 minutes ago, skylinebey said:

Does the brake booster go bad?

They can and do, but that leads to a hard pedal, not a mushy pedal.

[skylinebey]

I have replaced the original calipers with the upgraded calipers from the R34GTT model mines was the GT  NA.

 

[KiwiRS4T]

5 minutes ago, skylinebey said:

I have replaced the original calipers with the upgraded calipers from the R34GTT model mines was the GT  NA.

 

Presumably with used units. You need to check each wheel.

Another possible source of  new M/C is Kudos Motorsport.

I presume you have replaced the old fluid with new and properly bled the system?

 

[GTSBoy]

2 minutes ago, skylinebey said:

I have replaced the original calipers with the upgraded calipers from the R34GTT model mines was the GT  NA.

So, when did the brakes become spongey? After you did that?

[skylinebey]

The old caliper had a frozen piston and rusted .

I cleaned up the piston and resealed that caliper and the brakes became spongy.

So I then replaced with the bigger Gtt calipers and 

Pedal was still spongy?

I then checked the Gtt caliper to see if there was a leaky seal. The was no leak.

But still spongy , Then I thought the larger caliper working with the original MC was causing the spongy .

So thats how I got to the MC being the problem... because it happened when the Orignal caliper went bad.

I even replaced the ABS unit. Still same response.

 

 

Edited April 2, 2020 by skylinebey

[GTSBoy]

Now it sounds like a bleeding problem.

[KiwiRS4T]

If you fitted a dry abs unit you can have trouble bleeding the system.

[skylinebey]

What is the proper procedure bleeding with a dry ABS?

Thanks.

 

[KiwiRS4T]

8 hours ago, skylinebey said:

What is the proper procedure bleeding with a dry ABS?

Thanks.

 

Sorry I don't know. I have always made sure to keep air out of the ABS unit. Some cars have small bleeder screws, some need a pressure bleeder and for some you need a scan tool to open and close solenoids. The answer may be in the workshop manual or hopefully someone else may be able to help.

[skylinebey]

Thanks for your help replying.

I was hope someone else can get further insight into the ABS brake bleeding.

 

regards

[GTSBoy]

I am 100% sure that the procedure for bleeding the ABS has been posted before. Search, and ye shall find.

By the way, it is a complete prick of a task.

Also, when it comes to (vital safety) stuff like brakes, if you really do not know enough to solve your own problems, you should really consider using a professional to fix them. Just sayin'.

[Duncan]

My experience is with R32 GTR, being 10 years newer there may be easier ways to do it in an R34

It is a complete prick of a task.

Ultimately I pressure bled the system - 4 calipers (8 nipples), in order of furthest to closet to the master cylinder (so RR, LR, RF, LF) and then the 2 nipples on the top of the ABS.  Of course, since there was air in the ABS unit it was unsatisfactory, and since this was happening during a rally I needed to deal with it. So, after each stage I bled the ABS again (during the stage each time you trigger the abs all the little solenoids and things open and close moving air through the system).  Still sucked. After the event I then did a full bleed and it came up good

So, pressure bleeding makes it much easier because a single person can do it with less effort, and the ABS didn't come good simply by bleeding it static, it needed to be cycled a whole bunch of times before the air all moved out.

Hopefully R34 has some sort of ABS bleeding mode you can put it in instead of having to drive it and activate ABS over and over again...

[skylinebey]

Thanks

i live on an island , finding mechanics that specialize in just brakes is difficult. So you learn how to do things yourself. I practice safety that is why the car has been parked for almost a year now.  I will not drive it until this issue is resolved the right way. 
I have a brake vacuum kit to assist with the bleeding of the lines.

I have a software to run diagnostics on the car I will see if it has the ABS troubleshooting.

I will try as you recommended. Thanks again, like I said earlier specialized is hard to find. 
I appreciate the time you took to help me.??

[niZmO_Man]

Bleed ABS, drive around and slam brakes. Repeat until pedal pressure improves.