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Datsun 240Z L28 stroker – A simple bleed of the brakes?


On a recent test drive for the Datsun
240Z as part of this big mega squirt ignition only build, the brakes
became a bit spongy I’m not sure why and as a matter of safety I’m going to
investigate. [music] Hi guys! Check out the description notes for a timestamp
breakdown of this episode as well as the other social media platforms we’re on. If
we’re meeting for the first time consider subscribing as well. This episode, yeah,
I’m looking at the brake system on this car. Previously I put together my megasquirt ignition only, there was car show on less than a kilometer down the road,
thought I’d drop it down there. You can see that video in which I found that out
the episode after the drive. It will be in the link in the cards. Um, took it for a drive.
Brakes felt a little bit spongy and there’s some pedal presses where it
illuminated the brake light. On the 71 240Zs, on mine anyway, that’s
triggered by a differential block where when the pressure between the front
and the rear circuit exceeds a certain value it pushes a plunger inside the
assembly which grounds out a trigger it illuminates your dash, the warning light
in your dash. The brakes on this were serviced in 2017 it’s now a 2019. ‘Bout two
years. I’m hoping it’s just a simple bleed will fix it because I really want
to get onto the road tuning this engine but safety, if you don’t have functioning
or correctly functioning brakes that’s a bit of an issue for me. Need to
be safe. So normally I’ll just bleed the brakes with the car sitting on the
ground. I’ve done it a few times and I kinda remember where the bleed, bleed
nipple is so. Um I’ll have a start and just just see. Get into it. So I think the
culprit was the front circuit reservoir. It was a bit low so I just proceeded
to top it up with a bit of my favorite Penrite super dot 4 brake fluid. So I
just jumped into that circuit and started bleeding it. Got that done
then I started looking at the rear circuit, um, and I totally forgot that
it’s a been a recurring thing and for as long as I can remember it’s been like it.
The passenger side rear drum brake cylinder, err, so that’s the short
line, not the long line, for the rear circuit has had…I totally forgot about
it. I probably have notes in my little book that says “fix this next time” and I just
go “I’ll do it next time”. The bleed nipple in the cylinder has
sheared off down at the base, doesn’t leak, but it means that haven’t been able
to bleed it. So I think as a matter of safety, it’s probably something, it’s long
overdue, so I should do it. And if I’m going to the effort of
rebuilding the rear drums or pulling it out anyway – yeah it’s not up on the car
change it’s something we’ll have to pull the cylinder it and do it off the car –
well if I’m gonna pull that off I might as well pull the other one off and have a
look at that and potentially rebuild the brakes. And if I’m going to do the rear
brakes, I might as well do the front brakes. If I’m gonna do the front brakes
I might as well do the master cylinder as well. Bummed that I was…just keen to get
onto tuning this thing but I want to be safe. Safety is more important to me.
So at this juncture I’m gonna have to stop do the tuning and I’m going to
rebuild the brake system. Whether that means I get new parts, new built
components or rebuild the old ones, don’t know. I’ll just have to have a look to
see what the old ones alright. But what I’ll do is I’ll get this car up on
some, make, make it safe on some stands and I’ll show you the sheared off
bleed from the we are wheel cylinder and I might just take you through my
inspection process. Hmm. Anyway, bit of a bummer. [music] I do occasionally get asked about that
the tyres and rims on the Datsun and what I’ve got running on this there Rota RB-Rs. These are 17″ by 8.5″ running
235/45 rubber. Um, not sort of the offset for these. These rims
came with the car but I think the key, key thing I like about these is these
just squeeze underneath the rear guards, underneath all the guards. The previous
owner did trim a little bit out of the rear guard and a little bit of just
maybe a half the thickness on the fold at the top to fit him. But I mean they fit
pretty good. Um quite wide. I think they look pretty good. But here that’s if you’re
interested in knowing, that’s what’s on this car. Okay under the car with teh culprit so to speak. So this is the passenger, side well in
Australia terms, passenger side rear drum brake cylinder. Right there. That
should be a bleed nipple and as you can see it’s not so that’s what we gotta
deal with. You can seen near centre of frame that’s that’s the proper unbroken
bleed nipple that’s what it’s supposed to look like so. Apologies if it’s a
little bit dark but best I got at the moment. So you can get this drum off.
Now it should be fairly loose and if it’s not loose there are means to loosen
off the drum shoes but we’ll just give it a shot. Fairly loose. I’ll check these out. A few cracks in the lining. Shoe thickness is getting a bit thin, but yeah, that’s this is
the drum assembly. Two shoes. Cylinder the down on the bottom here with the
adjuster and some Springs What does it look like? They don’t look too old. The rubbers look in fairly good nick. Yeah the rubbers don’t seem very perished So I’ll go pull the drum off the the other side
have a bit of a gander at that see if it’s in similar condition to that and
then I’ll move on to the front cylinder. On thing I do note is I think my break lines a new. Um I did have Pedders put some shocks in it. I’ve got Tokito,
sorry Koni adjustable shocks in here. I put have them put in by Pedders before
I shifted to where I am now a couple of years ago and I’m sure I got them to put
new brake the new flex on brake lines in because they are very not perished in
look in good nick. So I’ll have to get the the invoice of works of what they did
for me just to check but it’s another thing you should always check to make
sure there’s nothing perished and all the lines are in good nick. And if you
interested that’s the that’s a little bit of the Zed story exhaust I got in
this car with the JDM muffler. It’s a bit dirty at this end with the clean ends out
there and this is the new centre pipe that I installed between here and the
headers. So if you’re interested in seeing that video will show up in the
cards with just that installing and there’s a bit of a sound check. But I really
like the Zstory stuff its good quality. Driver-side, Australian drivers side, or right hand side drum. See if it’s the same as the other one. The lining in the
drum seems to be pretty good nick. Only a hand full of cracks. I also have to
check this for maximum diameter see if it, um, means replacing. I think I could
get these new or with these re-sleeved. Ah a little bit of brake dust in this one. in this one you got the brake cylinder
here that when you apply pedal on the brake it pushes outwards and pushes on
the shoes which in turn push on the drum. Here is the adjuster which you use to align the these shoes so they just in
contact with the drum so there’s not excessive travel. This here, go can see its a
bit of a lever here. It goes through the dust cover seal on the back of the
brake dust cover on the on the back here. it’s it’s connected to hand break. When you apply
your hand brake it pushes on I believe the rear shoe it forces it just pushes it
out to be the hand brake. In this instance here you can see this
particular one has got some some cadmium colored lor zinc colored components
which lead me to believe this one’s been replaced. The seals look like you might
have been a replacement or whole replacement unit. There’s nothing on the
cylinder that suggests it’s just that though it’s just other than it looks new.
The seals are in good nick. Yeah these drums getting a bit thinner. I can’t
remember the spec but yeah they don’t one of the problems with drums is
because this is a fairly fixed point that doesn’t get adjusted here they
don’t get even wear. They’re all being pushed in and out from this bottom spot
sort of tilting in and out this way. So you you don’t get a full fully even wear
which is fair enough part and parcel having drum breaks. But I can see my
materials getting a bit thinner so while I’m working here I might see if, either, I
got some drum some shoes in my bits and pieces or I’ll get some. But yeah that’s
what a drum brake looks like on the back of a Datsun 240z. I hope
that’s helpful to someone. This is just the drum one of the drums. The drums,
on a Datsun 240z at least, they’re steel lined alloy drum. So it’s a steel liner in
there. I don’t know if you can see it. These are actually in fairly good nick. There
is some some little crazing cracks in the surface but that’s less than a dozen
of them and I’m not too worried about that. I think these are the original ones
because you know we’ve got some busted fins here. Maximum run out according to
the engraving embossment is 230 millimeters 9 inches 55 thou. I’m
interested know if anyone knows how to determine if these are original ones or
not. There’s an embossment E41 on here. I don’t know if that gives any
indication but yeah I’d be interested to know if how to determine if you have the
hubs are, the drum’s are original. I’ll put this back on because I lots of
all children are in I’ll probably loosely pick the wheels cuz I don’t
particularly want them to be getting brake dust on there hands. Drivers side or
right-hand side. Um, doesn’t appear to be much of a lip. The disc brake seems to be
in good nick. No oil or grease running out of it. Brake pads are getting a bit thin though. Er no. They got plenty of space. Yeah I don’t know if you can see there’s there’s new brake lines
in there. So yeah definitely got them installed when Pedders did the
work for me. which they did a good job too by the way. so these are the Sumitomo S16 calipers
I believe. They called the twin piston ones fairly standard Datsuns. These actually fairly common caliper. I’ve got a 1981 XT 130 Toyota
Corona that has these on as well. So I got a few spare. I looted the original
pair for the Corona from a Volvo in a wreckers. So they’re fairly common. I might do, so that doesn’t feel like there’s much of a lip at all. See if I
can get my verniers in there on, spot on 12 mil. I think that’s within spec I’ll just check but I
don’t really want to be replacing the rotors is if I don’t need to. And like I can’t see
any crazing or anything in there. No lip What I did have planned to do though
my long-term vision for the front brakes is get a set of Sumitomo MK 63s which is
the FIA homologated four pot Pistons that work with the standard master cylinder. I
think rather than do a Toyota S12+8, you know Hilux or Land Cruiser, swap
which would require a different master cylinder, what I really want is I want
the FIA ones but they’re few and far between and cost a lot of money now so.
If someone came up for reasonable price are probably purchase them and
rebuild them and put them on how. But I think, I think I will take a set of my,
I’m pretty sure I’ve got an old set, and a rebuild kit. I’ll rebuild these up and
then just swap them over. But yeah. I’ll have to think about what color I
should color these. I’ve really been a fan of funny colored brakes on a car
unless it came from standard. I think I might get these sandblasted up and just
leave them in the natural alloy color. I’m have a look at the the other side
and see what’s it’s like but um seems to be in fairly good nick and that hub
doesn’t feel like…a bit of tightness…but it certainly doesn’t feel like theres
bearing problems or I’d need to do bearings. Good stuff! So these are my spare
S16 calipers which I think I’ll rebuild using these kits. I found some
old Protex kits in my bits and pieces which I’ve verified that that is still
the current kit, they still sell this. I do like Protex but I mean if you, there
Australian made which doesn’t help folks outside this country. But I’ll still
put a link to this kit in the the notes. Um, also came across some rebonded
brakes. What are these? Yeah bonded breaks. I don’t nothing
totally new, they might be totally new. But anyway I got some some
drum brake shoes and the other thing I came across was some some brand new
brake pads. TRW I can’t remember a good brand or not. Probably are reasonably good
brands. But yeah so it looks like a little bits and pieces to rebuild the
front, um, got drum shoes with the master cylinder I’ll likely get that, send
that away and get that stainless steel sleeve because if I can follow my dream
of getting MK 63 calipers that master cylinder will still be good. I did look at
brand new ones but that seems to be a bit big hit and miss a bit hard to tell
if what a supplier would supply would be the one with the the reservoirs and the
correct orientation um and I’m not really interested in swapping over lines.
I’d much rather have a look be the regional product so it’s likely that
that master cylinder will come out and I’ll send it away would be stainless steel
sleeve so last for life. The drum cylinders I will probably, not
probably, I’ll just put a rebuild kit through them. I’m not entirely set on
maintaining drums the rest of life. I mean there is disc brake options you can
buy a new kits so he can fit like R31 Skyline rear brakes to it but. I think
they look fairly new so I might just put a rebuild kit through them and stick them
back in with new drummer shoes. I am bummed that I’ve got to hold up and
can’t get to tuning the L28, the stroker motor with the round top SUs.
I was looking forward to that. I don’t know if you guys are still
interested in the project of trying it 200 rear-wheel horsepower to this motor
with round top Sus. I’d love to hear it in the comments if you still are. I mean
I have thought that this car is laid up for a little bit, you know, is there
opportunity to to take the round top SUs off and put triple carbs or EFI on
or undertake a bigger project. Dunno. Car’s got to be safe. So i’ll fix
these brakes and then worry about Tuning. iIf you liked this video or
shared in a similar pain or frustration it would appreciate a like. Have a look
at what YouTube recommends from the channel as well as, just, I’ll flash up the
Megasquirt only ignition build playlist for you to look at. If you’re not a
subscriber consider subscribing and thank you for watching!

4 thoughts on “Datsun 240Z L28 stroker – A simple bleed of the brakes?

  1. You don't have to change the Master Cylinder to fit toyota brakes just put on a bigger front brake Reservoir.
    They are good brake pads ,but you have to get them hot and cool down before they work there best .
    Put in 6 fuel injectors off a skyline and still run the SU's as throttle bodies with the dash pots taken out .
    Every part you showed us ,i sell,so let me know if you need anything. except for 240Z rear wheel cylinders
    very hard to find

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