The Disc Brake conversion thread
- Thread starter Paul Oliver
- Start date
Good job [^] well done 
"You,re only supposed to blow the bloody SLIDING doors off"
"You,re only supposed to blow the bloody SLIDING doors off"
Thanks all,
Forgot in the excitement to say that I still haven't managed to get the stub axles shortened. Having trouble contacting my friend, as I only have business contacts and had relocated since I last saw him. He was getting on in years and suspect he may have retired. I no longer have access to a lathe myself and know there are other machine shops in the area, but it's always reassuring to use someone whos work you know and he was always super accurate.
Cheers Stephen
Forgot in the excitement to say that I still haven't managed to get the stub axles shortened. Having trouble contacting my friend, as I only have business contacts and had relocated since I last saw him. He was getting on in years and suspect he may have retired. I no longer have access to a lathe myself and know there are other machine shops in the area, but it's always reassuring to use someone whos work you know and he was always super accurate.
Cheers Stephen
Hi all
Back again to update what’s been happening. I thought I should start looking into the hydraulics of the braking system, seeing as the brakes are now pretty much sorted. Firstly I got hold of a set of rubber brake hoses from the same model Commodore that I got the disc callipers from. They should be long enough and have the correct banjo fittings for the callipers.
I will be replacing the original fixed steel brake lines as they have seen better days, plus they go to the wrong place as I will be running the callipers in front of the front axles. I still need to check the sizing and flaring arrangement for the other end, but all in good time.
I did a little research on the Commodore braking system and discovered they have a dual sized master cylinder. Apparently due to the need to displace such a large amount of fluid for the front callipers compared to the rear callipers the master cylinder is made up of two differently sized sections. The section that is for the front brakes is 1.25” bore and the rear 1” so everything should be fine for the front brakes, but when checking a Navara for my rear drums, I found they used a 15/16” master cylinder, so I might need to find some larger cylinders for the rear drums, more homework!
The Commodore brake master cylinder is quite compact, rather than being one long cylinder with two pistons one in front of the other, it does a “u” turn and comes back with the different sized cylinders next to each other.
I hadn’t seen this before, but it solves many of the problems that I had anticipated. The reservoir is a little too tall, but it is easily removed and should be able to be modified to a remote reservoir set-up. Most importantly, for a dual system master cylinder, it’s only about ½” longer than the standard Commer unit. I will need to weld a larger flange plate to the Commer mounting bracket with new fixing holes and open the centre hole from 1.25” to 1.5”. The Commer piston actuating rod will fit, with a couple of fiddly mods to make me happy.
The best news of all was the prices. The brake hoses cost $22 a pair and the master cylinder, which I’ve seen advertised for up to $200, cost just $35. Yes they are second hand, but came off a car around 5 years old and will have many years of service left in them.
The last things on my “braking list” to be investigated are a suitable remote brake booster and a load sensing proportioning valve for the rear brakes. The remote booster may need to be a new unit as there are few, if any cars in the recent past that have them fitted. The rear load valve will be easier, most Jap utes and vans have one fitted, but might start by looking at the Navara unit to match my diff/rear drums and keep the rear brake line threads consistent. I recall seeing that some of the later Commer/Dodge vans also had these fitted and think it worth including after all the other work that has gone into the overall braking system in my van
So that’s the plan, now just a case of getting it done.
Cheers Stephen
Back again to update what’s been happening. I thought I should start looking into the hydraulics of the braking system, seeing as the brakes are now pretty much sorted. Firstly I got hold of a set of rubber brake hoses from the same model Commodore that I got the disc callipers from. They should be long enough and have the correct banjo fittings for the callipers.
I will be replacing the original fixed steel brake lines as they have seen better days, plus they go to the wrong place as I will be running the callipers in front of the front axles. I still need to check the sizing and flaring arrangement for the other end, but all in good time.
I did a little research on the Commodore braking system and discovered they have a dual sized master cylinder. Apparently due to the need to displace such a large amount of fluid for the front callipers compared to the rear callipers the master cylinder is made up of two differently sized sections. The section that is for the front brakes is 1.25” bore and the rear 1” so everything should be fine for the front brakes, but when checking a Navara for my rear drums, I found they used a 15/16” master cylinder, so I might need to find some larger cylinders for the rear drums, more homework!
The Commodore brake master cylinder is quite compact, rather than being one long cylinder with two pistons one in front of the other, it does a “u” turn and comes back with the different sized cylinders next to each other.
I hadn’t seen this before, but it solves many of the problems that I had anticipated. The reservoir is a little too tall, but it is easily removed and should be able to be modified to a remote reservoir set-up. Most importantly, for a dual system master cylinder, it’s only about ½” longer than the standard Commer unit. I will need to weld a larger flange plate to the Commer mounting bracket with new fixing holes and open the centre hole from 1.25” to 1.5”. The Commer piston actuating rod will fit, with a couple of fiddly mods to make me happy.
The best news of all was the prices. The brake hoses cost $22 a pair and the master cylinder, which I’ve seen advertised for up to $200, cost just $35. Yes they are second hand, but came off a car around 5 years old and will have many years of service left in them.
The last things on my “braking list” to be investigated are a suitable remote brake booster and a load sensing proportioning valve for the rear brakes. The remote booster may need to be a new unit as there are few, if any cars in the recent past that have them fitted. The rear load valve will be easier, most Jap utes and vans have one fitted, but might start by looking at the Navara unit to match my diff/rear drums and keep the rear brake line threads consistent. I recall seeing that some of the later Commer/Dodge vans also had these fitted and think it worth including after all the other work that has gone into the overall braking system in my van
So that’s the plan, now just a case of getting it done.
Cheers Stephen
Hi all
Talk about applying some pressure, Panky!! Just to keep you happy, I managed to pick up the steel plate needed to mount the new brake master cylinder, get it drilled, welded on and rough assembled. Once it has a coat of paint it should look like an original factory set-up.
Now the fiddly stuff I mentioned with the piston rod as there is no circlip in the end of the cylinder to retain the piston rod. I will also be spending some time on the internet tonight, trying to find some remote type fittings so the reservoir can be relocated.
Cheers for now
Stephen
Talk about applying some pressure, Panky!! Just to keep you happy, I managed to pick up the steel plate needed to mount the new brake master cylinder, get it drilled, welded on and rough assembled. Once it has a coat of paint it should look like an original factory set-up.
Now the fiddly stuff I mentioned with the piston rod as there is no circlip in the end of the cylinder to retain the piston rod. I will also be spending some time on the internet tonight, trying to find some remote type fittings so the reservoir can be relocated.
Cheers for now
Stephen
Thanks Chamba
The trick to this type of modification, or any other for that matter, is to look at everything on anything. I work on the principle that every car has at least one good or great idea, you just have to find it, then see if you have a use for it.
Unfortunately this is becoming harder every year as old style wreckers here become harder to find in the Sydney metropolitan areas. I am now limited to 2 yards where they have hundreds of cars, one is more organised than the other, but you can wander around both for hours just looking and measuring things. The added bonus of having a camera on you mobile phone these days makes it easier for recalling things that might be of use.
It also helps if you have been playing with cars and motorbikes since you were a kid. I can understand how people can get a little overwhelmed with these sort of modifications, but If broken down into its components it's pretty straight forward.
For me, I have huge respect for the structural rust repair work you guys over there take on. It's an area that I don't really enjoy, but will eventually have to tackle on my van. The rust in my van is quite superficial cosmetic stuff that many forum members would consider a dream compared with the work they have done.
At times I think it would be nice to win the lottery and pay someone else to do it all, but what would be the fun of that.
As I've said before, if in doubt ask questions, that is the joy of forums like this.
Cheers Stephen
The trick to this type of modification, or any other for that matter, is to look at everything on anything. I work on the principle that every car has at least one good or great idea, you just have to find it, then see if you have a use for it.
Unfortunately this is becoming harder every year as old style wreckers here become harder to find in the Sydney metropolitan areas. I am now limited to 2 yards where they have hundreds of cars, one is more organised than the other, but you can wander around both for hours just looking and measuring things. The added bonus of having a camera on you mobile phone these days makes it easier for recalling things that might be of use.
It also helps if you have been playing with cars and motorbikes since you were a kid. I can understand how people can get a little overwhelmed with these sort of modifications, but If broken down into its components it's pretty straight forward.
For me, I have huge respect for the structural rust repair work you guys over there take on. It's an area that I don't really enjoy, but will eventually have to tackle on my van. The rust in my van is quite superficial cosmetic stuff that many forum members would consider a dream compared with the work they have done.
At times I think it would be nice to win the lottery and pay someone else to do it all, but what would be the fun of that.
As I've said before, if in doubt ask questions, that is the joy of forums like this.
Cheers Stephen
Hi all
Thought I better see how the brake master cylinder fits in the van, before I get too carried away. I bolted it all up today and was relieved when it fit, with the pedal height spot on.
The bolt on the end of the cylinder is for a support bracket when fitted to the Commodore. I fitted the metal guard that protects the master cylinders to check the clearance and it just sits against the end of the cylinder, so with a hole in the right place that will become its new support bracket.
You can see that there isn't much room for a reservoir, which is why I need to go to a remote set up. I've found a hot rod business that does a stainless steel adaptor that plugs in and has threaded fittings for the rest of the plumbing, just awaiting a reply on cost and delivery time.
I will sort the clutch cylinder out soon seeing as I am poking around in that area and will need to remove it to clean everything up. Lots of surface rust on the areas that aren't caked in grease or mud, that will be a fun day!
Happy with the outcome it was all removed, sand blasted and given a good coat of red oxide primer and now hang out to dry.
Cheers Stephen
Thought I better see how the brake master cylinder fits in the van, before I get too carried away. I bolted it all up today and was relieved when it fit, with the pedal height spot on.
The bolt on the end of the cylinder is for a support bracket when fitted to the Commodore. I fitted the metal guard that protects the master cylinders to check the clearance and it just sits against the end of the cylinder, so with a hole in the right place that will become its new support bracket.
You can see that there isn't much room for a reservoir, which is why I need to go to a remote set up. I've found a hot rod business that does a stainless steel adaptor that plugs in and has threaded fittings for the rest of the plumbing, just awaiting a reply on cost and delivery time.
I will sort the clutch cylinder out soon seeing as I am poking around in that area and will need to remove it to clean everything up. Lots of surface rust on the areas that aren't caked in grease or mud, that will be a fun day!
Happy with the outcome it was all removed, sand blasted and given a good coat of red oxide primer and now hang out to dry.
Cheers Stephen
Looks good nice to have dual circuit too [8D]
"You,re only supposed to blow the bloody SLIDING doors off"
nice to have dual circuit too [8D]
"You,re only supposed to blow the bloody SLIDING doors off"
Hi all,
Solved a problem that had giving me a little grief today, retaining the brake piston rod in the brake master cylinder. As the master cylinder is off a car with a brake booster there was no circlip to hold the piston in place. The standard rod was the perfect length and the hole it goes in is quite deep and had no chance of falling out, but I felt it would be best to have something retaining it.
The solution ended up being quite simple, I ground down the end of the rod so the existing retaining washer could be removed, then tapped the hole in the end of the cylinder 1/4" BSP. The rod was ground down again so that it could pass through a 1/4" BSP nipple, which was then cut down to become a retaining nut. The end of the rod was rewelded and ground into the necessary mushroom shape so the nut couldn't slide off. A small piece of nylon tube was pushed over the mushroom head to act like a gland packing the hold the rod in place, but still allow some give, add a touch of Loctite and job done.
After bolting everything together, it seemed to work fine with just enough clearance between the rod and retaining nut.
I will now need to find some sort of rubber boot to give it some protection, like on the standard brake cylinder and that part of the puzzle will be complete.
One thing I don't know is how heavy the pedal will eventually be. I had thought of fitting a remote booster, but from what I've read I would need to fit one for the front brakes and another for the rear, as it is a split system. Let me know if I'm wrong, but for now fingers crossed, it will be OK.
Cheers Stephen
Solved a problem that had giving me a little grief today, retaining the brake piston rod in the brake master cylinder. As the master cylinder is off a car with a brake booster there was no circlip to hold the piston in place. The standard rod was the perfect length and the hole it goes in is quite deep and had no chance of falling out, but I felt it would be best to have something retaining it.
The solution ended up being quite simple, I ground down the end of the rod so the existing retaining washer could be removed, then tapped the hole in the end of the cylinder 1/4" BSP. The rod was ground down again so that it could pass through a 1/4" BSP nipple, which was then cut down to become a retaining nut. The end of the rod was rewelded and ground into the necessary mushroom shape so the nut couldn't slide off. A small piece of nylon tube was pushed over the mushroom head to act like a gland packing the hold the rod in place, but still allow some give, add a touch of Loctite and job done.
After bolting everything together, it seemed to work fine with just enough clearance between the rod and retaining nut.
I will now need to find some sort of rubber boot to give it some protection, like on the standard brake cylinder and that part of the puzzle will be complete.
One thing I don't know is how heavy the pedal will eventually be. I had thought of fitting a remote booster, but from what I've read I would need to fit one for the front brakes and another for the rear, as it is a split system. Let me know if I'm wrong, but for now fingers crossed, it will be OK.
Cheers Stephen
You should be alright with just fitting one to the front brakes
"You,re only supposed to blow the bloody SLIDING doors off"
"You,re only supposed to blow the bloody SLIDING doors off"
quote:
Originally posted by Suinnyboy
I will now need to find some sort of rubber boot to give it some protection, like on the standard brake cylinder and that part of the puzzle will be complete.
Maybe the rubber boot off a ball joint would do the trick
Two's company
Originally posted by Suinnyboy
I will now need to find some sort of rubber boot to give it some protection, like on the standard brake cylinder and that part of the puzzle will be complete.
Maybe the rubber boot off a ball joint would do the trick
Two's company
Dodgee Bruce
New Member
AAhhhh i cant see any of the photos , also any updates???? been a few years now!!!
, also any updates???? been a few years now!!!