Jump to content
SAU Community

Recommended Posts

G'day guys, finished putting in my hydraulic handbrake today and I'm having issues, there is pressure in the handbrake but it's not locking the rear wheels.

I have bled the whole brake system and still no go.

It's not running a separate booster just taped into the rear brake line.

My next plan of attack is to machine the rotors and fit new pads and see if that helps.

Any other ideas would be greatly appreciated.

Cheers - Trent

Link to comment
https://www.sau.com.au/forums/topic/392201-hydraulic-handbrake-setup/
Share on other sites

I'm not sure if there's a valve at the main MC that will stop it from happening. The thing is, you have to close your eyes and imagine the insides of the main MC. In the back half of it there is a piston. In front of the piston in the cylinder itself, there is brake fluid. At the top of the cylinder there is a hole connected to the back half of the fluid reservior. At the bottom of the cylinder (and further forward than the hole in the top) there is a hole that leads to your rear brake line.

So when you push the brake pedal, the piston moves forwards and blocks off the hole at the top (stopping fluid from being pushed up into the reservoir) and the resulting displacement of fluid gets pushed out the brake line to work your brakes. The pads move to take up the knock off, then the pressure in the line rises (with no further displacement). When you let off the pedal, the reverse happens. The pressure is relaxed and pad knock off pushes the little bit of displaced fluid back into the cylinder. If there is ever any leakage, the loss is made up from the reservior.

But what if you jam fluid into the same brake line at some point half way along with another, separate master cylinder? (Sound familiar?) You squeeze fluid into the line, and you expect it to raise the pressure, this pushing the pads onto the disk, as if you were using the normal MC. But I reckon that what happens is that the fluid takes the easy path up into the main MC's reserviour, because that is all open to flow.

I don't know about hydraulic handbrakes real well, because I've never had need or want to play with them, but I expect that if they get put on the normal main rear brake line then you have to pull some shenanigans with check valves or something to make them work.

Usually, a hydraulic handbrake "master" is not like a normal master. The fluid can only be pushed in one direction. The problems that can arise is if you plumb the master in the wrong way. My experience is that the fluid comes in the rear fitting and out the front fitting - so the fluid does a sort of "loop-the-loop" on its path from the MC to the rear brake.

Also, make sure the HB master has been bled properly before bleeding the rear brakes.

Q. - what is the reason for the hydraulic HB? Does it replace the existing HB, or is it additional to it? If it replaces the existing HB, make sure the car is ALWAYS parked in gear, because a hydraulic HB will gradually lose pressure and slowly release the handbrake. (been there, done that! car ended up across the road, and reportedly just missed another car that drove past the driveway)

It's for my drift car. And it is replacing my existing one.

Thanks for the heads up blind elk haha

Yeah we have it plumbed in with the fluid going into the rear fitting and out the top/front.

I'll give the hydraulic hb another bleed and see what happens.

I'm sure there is some very useful infomation in what you've written gtsboy but to me it's all jibberish :)

So many people have issues bleeding these correctly.

How Are you bleeding it?

What size master or you using on it?

GTSboy is talking about the compensation ports that allow fluid to go back into reservoir. These are blocked when you hit your foot pedal so fluid can't go back into reservoir.

Hydraulic handbrakes run a one way valve to compensate for what he is talking about. Hence If you put the lines back to front it would not work at all.

Standard master, any recommendations in what master to run? Maybe a r33 one?

To bleed it I'm undoing a fitting at the handbrake , giving it a few pumps then holding it engaged and tightening fitting, and repeating that process and then the same at the rear brakes with the foot brake.

I need to know now what a good master Replacment will be.

Thanks for the advice guys - Trent

I meant what size master on the HHB? Standard brake master won't be an issue.

I found best way to bleed it up is to bleed HHB master using the HHB lever as you were but also push foot pedal. Then do the same for rear calipers. (using both)

This is how I found get a better bleed and feel.

It's also important to get your free play right on the lever.

Thanks for that mate, I was at the workshop 2night and we took the brake booster out of my 180b and are now running that with the hydro. Final touches 2moro and we'll see how we go

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • As discussed in the previous post, the bushes in the 110 needed replacing. I took this opportunity to replace the castor bushes, the front lower control arm, lower the car and get the alignment dialled in with new tyres. I took it down to Alignment Motorsports on the GC to get this work done and also get more out of the Shockworks as I felt like I wasn't getting the full use out of them.  To cut a very long story short, it ended up being the case the passenger side castor arm wouldn't accept the brand new bush as the sleeve had worn badly enough to the point you could push the new bush in by hand and completely through. Trying a pair of TRD bushes didn't fix the issue either (I had originally gone with Hardrace bushes). We needed to urgently source another castor arm, and thankfully this was sourced and the guys at the shop worked on my car until 7pm on a Saturday to get everything done. The car rides a lot nicer now with the suspension dialled in properly. Lowered the car a little as well to suit the lower profile front tyres, and just bring the car down generally. Eternally thankful for the guys down at the shop to get the car sorted, we both pulled big favours from our contacts to get it done on the Saturday.  Also plugged in the new Stedi foglights into the S15, and even from a quick test in the garage I'm keen to see how they look out on the road. I had some concerns about the length of the LED body and whether it'd fit in the foglight housing but it's fine.  I've got a small window coming up next month where I'll likely get a little paint work done on the 110 to remove the rear wing, add a boot wing and roof wing, get the side skirt fixed up and colour match the little panel on the tail lights so that I can install some badges that I've kept in storage. I'm also tempted to put in a new pair of headlights on the 110.  Until then, here's some more pictures from Easter this year. 
    • I would put a fuel pressure gauge between the filter and the fuel rail, see if it's maintaining good fuel pressure at idle going up to the point when it stalls. Do you see any strange behavior in commanded fuel leading up to the point when it stalls? You might have to start going through the service manual and doing a long list of sensor tests if it's not the fuel system for whatever reason.
    • Hi,  Just joined the forum so I could share my "fix" of this problem. Might be of use to someone. Had the same hunting at idle issue on my V36 with VQ35HR engine after swapping the engine because the original one got overheated.  While changing the engine I made the mistake of cleaning the throttle bodies and tried all the tricks i could find to do a throttle relearn with no luck. Gave in and took it to a shop and they couldn't sort it. Then took it to my local Nissan dealership and they couldn't get it to idle properly. They said I'd need to replace the throttle bodies and the ecu probably costing more than the car is worth. So I had the idea of replacing the carbon I cleaned out with a thin layer of super glue and it's back to normal idle now. Bit rough but saved the car from the wreckers 🤣
    • After my last update, I went ahead with cleaning and restoring the entire fuel system. This included removing the tank and cleaning it with the Beyond Balistics solution, power washing it multiple times, drying it thoroughly, rinsing with IPA, drying again with heat gun and compressed air. Also, cleaning out the lines, fuel rail, and replacing the fuel pump with an OEM-style one. During the cleaning process, I replaced several hoses - including the breather hose on the fuel tank, which turned out to be the cause of the earlier fuel leak. This is what the old fuel filter looked like: Fuel tank before cleaning: Dirty Fuel Tank.mp4   Fuel tank after cleaning (some staining remains): Clean Fuel Tank.mp4 Both the OEM 270cc and new DeatschWerks 550cc injectors were cleaned professionally by a shop. Before reassembling everything, I tested the fuel flow by running the pump output into a container at the fuel filter location - flow looked good. I then fitted the new fuel filter and reassembled the rest of the system. Fuel Flow Test.mp4 Test 1 - 550cc injectors Ran the new fuel pump with its supplied diagonal strainer (different from OEM’s flat strainer) and my 550cc injectors using the same resized-injector map I had successfully used before. At first, it idled roughly and stalled when I applied throttle. Checked the spark plugs and found that they were fouled with carbon (likely from the earlier overly rich running when the injectors were clogged). After cleaning the plugs, the car started fine. However, it would only idle for 30–60 seconds before stalling, and while driving it would feel like a “fuel cut” after a few seconds - though it wouldn’t fully stall. Test 2 – Strainer swap Suspecting the diagonal strainer might not be reaching the tank bottom, I swapped it for the original flat strainer and filled the tank with ~45L of fuel. The issue persisted exactly the same. Test 3 – OEM injectors To eliminate tuning variables, I reinstalled the OEM 270cc injectors and reverted to the original map. Cleaned the spark plugs again just in-case. The stalling and “fuel cut” still remained.   At this stage, I suspect an intermittent power or connection fault at the fuel pump hanger, caused during the cleaning process. This has led me to look into getting Frenchy’s fuel hanger and replacing the unit entirely. TL;DR: Cleaned and restored the fuel system (tank, lines, rail, pump). Tested 550cc injectors with the same resized-injector map as before, but the car stalls at idle and experiences what feels like “fuel cut” after a few seconds of driving. Swapped back to OEM injectors with original map to rule out tuning, but the issue persists. Now suspecting an intermittent power or connection fault at the fuel pump hanger, possibly cause by the cleaning process.  
×
×
  • Create New...