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Username Post: Brake Line Sizing Help
Cruzin Okie
"2nd Year" Silver Supporting Member
Posts 676
Cruzin Okie
12-27-17 07:37 PM - Post#2719164    

I have a Jag IFS, and an S10 Blazer drum rear end in my 53 . If memory serves (doesn't usually) I have a 1 inch dual master cylinder. I'm going to be running all new lines, so I need some line size advice.

I know it has been discussed before, but I've not found it.

Thanks for your help, Johnnie.
Johnnie

1950 styleline deluxe sports coupe, 350 cid, TH 400, nova rear end. Gen IV Vintage air. SOLD!
1953 210 4 Door, 235 with Powerglide. All original except for the 1954 hood bird.

John 3:16


rrausch
"14th Year" Silver Supporting Member
Posts 13842
rrausch
12-27-17 08:50 PM - Post#2719167    

Good question. I have never seen this addressed with different front and rear suspensions.

On the stock '53 cars the smaller lines were 3/16ths in diameter for sure and the larger ones maybe 5/16ths. Not sure about the larger size right now.

But the real question is how do you match the brake line threads for both the master cylinder, the Jag front suspension and the S-10 rear?
1953 210 Convertible, 261 with dual Carter YF 966S carbs, P.S., Remote Bendix P.B. Booster... shade-tree restoration about done.



Cruzin Okie
"2nd Year" Silver Supporting Member
Posts 676
Cruzin Okie
12-27-17 09:15 PM - Post#2719172    

They make an adapter to go from the SAE to metric. They go between the steel lines and the Flex lines on the Jag. The rest of the system is standard threads. I got the part numbers from 53Chevy, when he did his Jag front end.
Johnnie

1950 styleline deluxe sports coupe, 350 cid, TH 400, nova rear end. Gen IV Vintage air. SOLD!
1953 210 4 Door, 235 with Powerglide. All original except for the 1954 hood bird.

John 3:16


rrausch
"14th Year" Silver Supporting Member
Posts 13842
rrausch
12-28-17 04:12 PM - Post#2719241    

Of course! Good to know somebody figgered that out.
1953 210 Convertible, 261 with dual Carter YF 966S carbs, P.S., Remote Bendix P.B. Booster... shade-tree restoration about done.



cbmkr56
Silver Supporting Member
Posts 1051
cbmkr56
12-28-17 05:15 PM - Post#2719257    

The jag uses 3/16" std brake line with the std flare, The nut on the jag line at the hose is female thread same flare just a female threaded nut.

I keep those nuts for the rubber hose to line connection here.

S10 rears are 3/16" brake line also but might have the metric nuts.

There is an adapter for the master cyl to fit the metric S10 nuts.
Cruzin Okie
"2nd Year" Silver Supporting Member
Posts 676
Cruzin Okie
12-28-17 05:46 PM - Post#2719264    

That's right on the fitting, I forgot that. Thank you sir. So I guess 3/16 all the way around.
Johnnie

1950 styleline deluxe sports coupe, 350 cid, TH 400, nova rear end. Gen IV Vintage air. SOLD!
1953 210 4 Door, 235 with Powerglide. All original except for the 1954 hood bird.

John 3:16


cbmkr56
Silver Supporting Member
Posts 1051
cbmkr56
12-28-17 06:22 PM - Post#2719267    

The boats in the Garage and we now have ice, I guess we have to work on our cars until it warms up.
Cruzin Okie
"2nd Year" Silver Supporting Member
Posts 676
Cruzin Okie
12-28-17 07:19 PM - Post#2719273    

That is for sure my friend. I walked out to the garage this afternoon to take some parts out for the car. I sat the parts on the boat and looked out at the lake, with no desire to go!! The bass boat has become a great storage area.
Johnnie

1950 styleline deluxe sports coupe, 350 cid, TH 400, nova rear end. Gen IV Vintage air. SOLD!
1953 210 4 Door, 235 with Powerglide. All original except for the 1954 hood bird.

John 3:16


Bel Air kiwi
"3rd Year" Silver Supporting Member
Posts 4256
Bel Air kiwi
12-30-17 02:49 AM - Post#2719400    

Hi CO, what year is your Jag front end? The first two versions were imperial thread and the series 3 was metricated.

I can make really good lines and returns etc when in a commercial workshop. Show quality stainless if you wan't to pay. But I can't do it with the cheap aftermarket tools that are flooding the market.

I borrow and share with professionals whose gear is five to ten times the price of the internet specials. The dilemma is that this gear is way beyond economic for hobbiests.

Cheers Kiwi
48 3100 RHD, 51 Deluxe 4DR RHD, 51 Bel Air parts car, 52 Bel Air P-Glide LHD. Others 23T, 32 Tudor, 58 Edsel pacer 4DR HDT, 79 F250 351C RHD. 69,70,82 Capri. No mobile, no TV, and no Jap cars.

And when it was laid to waste, they called it peace.

Cruzin Okie
"2nd Year" Silver Supporting Member
Posts 676
Cruzin Okie
12-30-17 08:55 AM - Post#2719417    

Hey Kiwi, I was about to send out a search party for you. I was expecting you to hop in there because this is right down you alley. I hope you had a great Christmas!!

It's an 89 xjs.
Johnnie

1950 styleline deluxe sports coupe, 350 cid, TH 400, nova rear end. Gen IV Vintage air. SOLD!
1953 210 4 Door, 235 with Powerglide. All original except for the 1954 hood bird.

John 3:16


Bel Air kiwi
"3rd Year" Silver Supporting Member
Posts 4256
Bel Air kiwi
12-30-17 01:29 PM - Post#2719444    

Hi Johnnie, Thanks for your kind thoughts. I had a great family Christmas and am now painting the house. Summer here.

To get the best out of those disc's you will need a big booster. This will tend to overpower your rear drums so an adjustable proportioning valve is the best fix as it means you can tune in the exact pressure difference you need.

Where about's are you putting your master cylinder?

Cheers Kiwi, all the best for the new year to you and yours.
48 3100 RHD, 51 Deluxe 4DR RHD, 51 Bel Air parts car, 52 Bel Air P-Glide LHD. Others 23T, 32 Tudor, 58 Edsel pacer 4DR HDT, 79 F250 351C RHD. 69,70,82 Capri. No mobile, no TV, and no Jap cars.

And when it was laid to waste, they called it peace.

Cruzin Okie
"2nd Year" Silver Supporting Member
Posts 676
Cruzin Okie
12-30-17 06:32 PM - Post#2719472    

Glad to hear you had a good one.

Master cylinder and booster mounted on the firewall. Walton Fabrication, firewall mounted swinging brake pedal, with dual booster.
Johnnie

1950 styleline deluxe sports coupe, 350 cid, TH 400, nova rear end. Gen IV Vintage air. SOLD!
1953 210 4 Door, 235 with Powerglide. All original except for the 1954 hood bird.

John 3:16


Bel Air kiwi
"3rd Year" Silver Supporting Member
Posts 4256
Bel Air kiwi
12-30-17 09:34 PM - Post#2719488    

Hi Johnnie, that Walton mount is a good piece of kit. I particularly like the dash brace as that's quite a bit of weight swinging of an access plate hole with the master and booster weight combined. When you add in the panic stop hit, it really matters.

You can get 3/16" brake nuts with either metric or imperial threads, sometimes they even have an imperial thread and a metric spanner size. Quite often find our imperial bleeders have 10mm spanner size.

I would use an adjustable type proportioning valve, not a kit one. If the dual master has an internal RLP then that will be the furthest from the pedal. Use that for the rear drums.
You won't need one on the front discs as gravity will do that job for you.

Plus having a 10 Psi RLP on the back and none on the disc end will bring their application time closer.

Cheers Kiwi
48 3100 RHD, 51 Deluxe 4DR RHD, 51 Bel Air parts car, 52 Bel Air P-Glide LHD. Others 23T, 32 Tudor, 58 Edsel pacer 4DR HDT, 79 F250 351C RHD. 69,70,82 Capri. No mobile, no TV, and no Jap cars.

And when it was laid to waste, they called it peace.

Cruzin Okie
"2nd Year" Silver Supporting Member
Posts 676
Cruzin Okie
12-31-17 03:11 PM - Post#2719556    

Thanks, Kiwi. I have a new chrome proportioning valve, but I will replace it with an adjustable one. Makes sense to me!!

I am always amazed at the knowledge and expertise found among you guys. If you ever have questions about the bible, I'm your man.
Johnnie

1950 styleline deluxe sports coupe, 350 cid, TH 400, nova rear end. Gen IV Vintage air. SOLD!
1953 210 4 Door, 235 with Powerglide. All original except for the 1954 hood bird.

John 3:16


Bel Air kiwi
"3rd Year" Silver Supporting Member
Posts 4256
Bel Air kiwi
01-01-18 06:59 AM - Post#2719626    

Hi Johnnie, Don't throw it away if you have already paid for it. Post an image and see if you can find from the supplier what values are built into it.

Its actually more likely to be a combination valve than just a plain proportioning valve and that was how the US market addressed Disc/Drum combinations OE.

Cheers Kiwi
48 3100 RHD, 51 Deluxe 4DR RHD, 51 Bel Air parts car, 52 Bel Air P-Glide LHD. Others 23T, 32 Tudor, 58 Edsel pacer 4DR HDT, 79 F250 351C RHD. 69,70,82 Capri. No mobile, no TV, and no Jap cars.

And when it was laid to waste, they called it peace.

Bel Air kiwi
"3rd Year" Silver Supporting Member
Posts 4256
Bel Air kiwi
01-05-18 06:14 AM - Post#2720074    

Hi Johnnie. If you have already bought a combination valve I suppose I should explain to you that they were a US market OE response to having boosted disc with drum rears.

The big problem is that they were vehicle range and manufacturer specific so you don't really know what values an Aftermarket one has, and you can't adjust them. Plus you are relying on the aftermarket to replicate the OE performance, and they are very fond of standardizing things that are not the same.

So a typical combination valve has two or three features.

The first one you are expecting is a pressure proportioning system so that as the brake pedal is applied the initial pressure is universal, but as it climbs up near 300 Psi the rear brake line pressure begins to be limited and only slowly rises up to say 450-500 Psi depending on the wheel cylinder size.
The front pressure on the disc end continues to rise un-restricted and can go way higher with a booster and big pedal ratio.

The next feature is they often have a failure switch built in which will trigger if the proportioning spool does some thing funny. This is only a problem when you need to bleed the unit as it needs to be locked out or substituted with a pin lock to allow the unit to bleed air out fully. Some are end pin in, some are end pin out and others are center pin locked.

The third and common feature they have is a little trick called a metering valve. What it is in essence is a bigger RLP put deliberately in backwards in the disc line.
You didn't think they were going to call it the "Front brakes hold off valve" but that is exactly what it does.
Typically they have values in the 25 Psi to 50 Psi range but I have not checked as we didn't use them.
What happens is that the disc brakes start working long before the brake springs in the rear have been overcome and the rear shoes are even starting to apply any retardation at all. So this generates a driver sensation that the rear wheels are trying to pass the fronts. Which they are because they aren't stopping yet. Its a sensation that disappears quickly as the usual response is more brake pressure which brings the back into line.
Although you would probably have to be on ice for it to matter, you definitely can feel it with big rear wheel cylinders.
So the OE fix in the US market was to hide this feel by stopping the discs from working until the rears were becoming effective.
So the braking wobble is gone, but so has the brakes sensitivity, and some of your reaction time.

Actually both the proportioning valve and the metering valve were not unnecessary. All that was needed were much smaller diameter rear wheel cylinders to work on the same pressure as the disc fronts.
If you make the wheel cylinder half the area, then it will need twice the pressure to apply the same force to the shoes.
And because they are small diameter they move further for a given pedal stroke so come in slightly quicker against the springs.

Please note that any values I have used here are entirely indicative only and what the values and direction of operation of any particular valve you have in your hand is your guess.

So what we did with anything like a Mustang or similar that came in with this stuff was bin it and fit the Australian Ford backing plate to 8-9" diffs. If it was a GM product we would bin the diff and the rest is as for Ford 9".

Cheers Kiwi
48 3100 RHD, 51 Deluxe 4DR RHD, 51 Bel Air parts car, 52 Bel Air P-Glide LHD. Others 23T, 32 Tudor, 58 Edsel pacer 4DR HDT, 79 F250 351C RHD. 69,70,82 Capri. No mobile, no TV, and no Jap cars.

And when it was laid to waste, they called it peace.

Cruzin Okie
"2nd Year" Silver Supporting Member
Posts 676
Cruzin Okie
01-06-18 05:03 PM - Post#2720267    

To say I understand would be an overstatement. Although, I do know more now than I did. Thanks Kiwi.
Johnnie

1950 styleline deluxe sports coupe, 350 cid, TH 400, nova rear end. Gen IV Vintage air. SOLD!
1953 210 4 Door, 235 with Powerglide. All original except for the 1954 hood bird.

John 3:16


Bel Air kiwi
"3rd Year" Silver Supporting Member
Posts 4256
Bel Air kiwi
01-08-18 03:30 AM - Post#2720411    

Hi Johnnie, what part is giving you trouble.

The proportioning side?
The bleeders?
The metering valve?

Can you tell me what size the wheel cylinders are on your S10 rear end?

Cheers Kiwi

48 3100 RHD, 51 Deluxe 4DR RHD, 51 Bel Air parts car, 52 Bel Air P-Glide LHD. Others 23T, 32 Tudor, 58 Edsel pacer 4DR HDT, 79 F250 351C RHD. 69,70,82 Capri. No mobile, no TV, and no Jap cars.

And when it was laid to waste, they called it peace.

Cruzin Okie
"2nd Year" Silver Supporting Member
Posts 676
Cruzin Okie
01-08-18 08:53 AM - Post#2720428    

Hey, Kiwi. None really. I asked what size lines I should run and you suggested an adjustable proportioning valve. I think that's a good idea. I can adjust it so the brakes work properly. As you said in your previous post, With the stock Chevy style Valve, I get what I get.

Thanks again, Johnnie
Johnnie

1950 styleline deluxe sports coupe, 350 cid, TH 400, nova rear end. Gen IV Vintage air. SOLD!
1953 210 4 Door, 235 with Powerglide. All original except for the 1954 hood bird.

John 3:16


Bel Air kiwi
"3rd Year" Silver Supporting Member
Posts 4256
Bel Air kiwi
01-08-18 11:57 AM - Post#2720441    

Hi Johnnie, That is true but primarily the use of the adjustable proportioning valve is to re-balance the breaking loads on a car when it is customized.

There are two forces in play here. Firstly disc brakes use and need higher line pressures than drum brakes. So the first part is limiting the amount of pressure in the drum part.

The second is that cars have a notional brake balance front to rear. In our years with with drum/drum the fronts single cylinder is larger than the rear so the its greater surface area applies more pressure on the front shoes than the back.

What an adjustable proportioning valve does is allow you to limit the maximum line pressure in the rear (Normally) so it doesn't lock up as the fronts get more pressure. This is done on custom builds as the parts swapping and testing to do it by parts sizing will be expensive for a one off situation.

At the heart of the issue is that the two styles of drum and disc work differently, at different pressures, with different rates of application and different abilities to dissipate heat.

If the S10 rear had wheel cylinders in the 1" range then a combination valve may work. If it has a small diameter like say 5/8" then by design it can tolerate a lot more pressure before having issues and may not work effectively with a combination valve.
Find out what wheel cylinder you have as the preset valve may be OK for you.

Brakes don't care what car they are on. Its about weight v speed, and front to rear balance.


Cheers Kiwi
48 3100 RHD, 51 Deluxe 4DR RHD, 51 Bel Air parts car, 52 Bel Air P-Glide LHD. Others 23T, 32 Tudor, 58 Edsel pacer 4DR HDT, 79 F250 351C RHD. 69,70,82 Capri. No mobile, no TV, and no Jap cars.

And when it was laid to waste, they called it peace.

Cruzin Okie
"2nd Year" Silver Supporting Member
Posts 676
Cruzin Okie
01-08-18 12:49 PM - Post#2720450    

Kiwi, the wheel cylinders are 7/8 bore.
Johnnie

1950 styleline deluxe sports coupe, 350 cid, TH 400, nova rear end. Gen IV Vintage air. SOLD!
1953 210 4 Door, 235 with Powerglide. All original except for the 1954 hood bird.

John 3:16


Bel Air kiwi
"3rd Year" Silver Supporting Member
Posts 4256
Bel Air kiwi
01-08-18 02:14 PM - Post#2720461    

Hi Johnnie, that probably means that they had balanced the brakes for disc v drum via reducing the wheel cylinder effectiveness.
Same pressure with less area = less power.
Did the original S10 have a prop valve?

Cheers Kiwi
48 3100 RHD, 51 Deluxe 4DR RHD, 51 Bel Air parts car, 52 Bel Air P-Glide LHD. Others 23T, 32 Tudor, 58 Edsel pacer 4DR HDT, 79 F250 351C RHD. 69,70,82 Capri. No mobile, no TV, and no Jap cars.

And when it was laid to waste, they called it peace.

Cruzin Okie
"2nd Year" Silver Supporting Member
Posts 676
Cruzin Okie
01-08-18 06:25 PM - Post#2720491    

Yes I think it did. I will look next time I'm over that way.
Johnnie

1950 styleline deluxe sports coupe, 350 cid, TH 400, nova rear end. Gen IV Vintage air. SOLD!
1953 210 4 Door, 235 with Powerglide. All original except for the 1954 hood bird.

John 3:16


Bel Air kiwi
"3rd Year" Silver Supporting Member
Posts 4256
Bel Air kiwi
01-09-18 05:37 PM - Post#2720603    

Hi Johnnie, If it has a factory combination valve, that would probably be the best one to use with its rear end.

We didn't get the S10 so I am not very familiar with them but I understand they have small 4 pot calipers on the front and a traditional self adjusting Bendix drum rear.

So their Master, Booster, valves and other bits should be within range if you use the jag front end which is a larger four pot system.

The thing you need to check is that on some trucks there is another type of proportioning valve which modulates the rear brakes depending on how much load is on the rear. These "load sensing" valves allow more pressure to the rear when the sensor feels the rear suspension compressed so you should be looking on the rear suspension for some sort of light linkage to a valve in the brake line. Might not have one on something this small.

Cheers Kiwi
48 3100 RHD, 51 Deluxe 4DR RHD, 51 Bel Air parts car, 52 Bel Air P-Glide LHD. Others 23T, 32 Tudor, 58 Edsel pacer 4DR HDT, 79 F250 351C RHD. 69,70,82 Capri. No mobile, no TV, and no Jap cars.

And when it was laid to waste, they called it peace.

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