Jag IFS Swap Questions

I'm gearing up for the jag swap into the F100. I've read through all of the threads I could find about it, and came up with a few questions.

1. What is needed to adapt the jag brakes to a regular system? I think I read in one thread that the Jag being a foreign car uses a different kind of caliper? Something about low volume/high pressure, or maybe its the other way around. Basically I'm wondering if I can use a regular disc/drum dual out master cylinder, adapt the brake lines, and it won't have weird issues?

2. Can I use my stock steering column and wheel? If so, how? I know on F100s the shaft is built into the steering box.

A few other notes- I plan to bolt it in instead of weld. That means I need to use that special Jaguar steering connector.

I'll post pics of the swap after I've pulled it off.

 

I've been using a Corvette m/c cylinder on mine for a few years now with no problems. Mines disc/disc since I am using both the front and the rear.

You can do the column just like the one in here.
http://www.jalopyjournal.com/forum/showthread.php?t=148978

If I remember correctly they are 3/4"-48 spline to the rack, Wildwood as well as a few others sell the proper u-joint for it.

 

i ***ume you are using xj6? the front calipers are 4 pot, jag m/c measure's 15/16 inch bore, the steering i have used a jag uj welded to a bar then on to a borgason uj, if i were you id cut the box of, then have the colum bored out and tig weld some splined shaft or d shape shaft to fit the uj, most of the brake fittings are imperial which is the same as you use i think

 

Are you runnin' drums on the rear ?? if so ,you'll need an adjustable proportionating valve ,,if you're gonna run the Jag rear Suspension too ,,get the Jag proportionating valve off the donor car ,,otherwise you'll be locking up those front wheels all the time ,,been there ,,done that too,, ,,

 

I plan to keep the rear drums. So I need the proportioning valve. But I think you guys answered my question that I don't need some kind of special master cylinder for the Jag brakes.

 

That depends on what series xj6 is being used.
They are not all 4 pot.

 

Which series are 4? Does it matter much? I'm getting the clip out of an '86 jag.

 

'86 will be 4 pot.
Mine is series 2 which is 4 pot.

 

Sweeeet.

 

How are you mounting this front end? Factory style with rubber insulators or solid?
If factory style then you will need to use the jag UJ (or similar) on the column which allows for changes in length due to the rubber mounting.

 

I rubber mounted mine on my F1, but it's not on the road yet. I called Borgeson about the "Z" joint on the jag, and they said to use their collapsable dd shaft, or telescoping shaft, I don't remember which one. It's the same type of shaft they sell for 4wd rock crawlers, which also need some change of length. Their catalog lists the sizes for the jag rack, match it to your steering column on the other end. BTW, the shaft will probably need to be cut as the rear mounted rack is fairly close to the steering column. If you look at the rubber bushings, you'll see the ifs can only move 3/8 of so, it doesn't have a huge amount of movement. There may be a company that makes a poly bushing for the front, that would restrict movement, but stiffen the ride. In road racing, we used to fill squishy stock rubber bushings with black silicone to stiffen them if we couldn't get a poly bushing.

 

I have used the whole Jag subframe from the firewall forward.
Include all original jag mountings, rack, sway bar etc.
Also the tilt unit for the Jag hood that I am using for a tilt front on my car.
I have a Caddy tilt/collapsible steering column which I have yet connected to the Jag adjustable joint off the rack.
Still trying to find a good solution.

 

Do I have to use a 15/16" bore or can I use the more common 1"?

EDIT: Is bigger better? I'm not running a booster if that makes a difference.

 

Bigger isn't always better with master cylinders. It needs to be right. It may take some trial and error on sizing due to the custom install, so stick with something common.

Take a Jag for a drive. Turn off the engine and try to pull up to a stop. (I have had one stall, same problem) I think you should probably look towards using a booster.

Also, I'd reccomend the Jag Z joint over a double D slider too. The Jag joint is all sealed bearings with zero backlash. I can't see a double D doing the job not having some backlash (or siezing up and tearing out your firewall)

 

You might call Curt Hamilton. 818-943-2323 He is an expert on Jag brakes.

 

Have a look at this on the UK hot rods site, it may be the answer to your problem.

http://www.uk-hotrods.co.uk/v2/garage_scene/me/page_1.php

Very comprehensive build up of a '53 F100, inc Jaguar IFS.

 

Thanks for the info. Did any Jags come with non-power brakes? I'd like to find out what the bore size was for those.

 

I'm not aware of any Jag not having power ***isted brakes (or any other car for that matter).

Disc brakes by design are not self energizing unlike the drum variety. Drum brakes "energize" as a conequence of the leading shoe wanting to wrap themselves into the drum. Think of it a bit like using a wire wheel attachment on your bench grinder. Lets say your holding a screwdriver and you push the blade end up into the wire wheel at the top, the wheel will bite that driver and will slow that wheel real quick . On the other hand if you point the blade down and bring it into contact with the wire wheel on the lower side as it is moving away from you the wheel will simply push it away but it wont bite like the other way. This is basically what happens with drum brakes. The lead shoe acts like the screwdriver pointing up and the trail shoe acts like the screwdriver pointing down. In the same way, the lead shoe tends to lock up the drum.

This is the self energizing prinicple in action. Disc brake on the other hand don't have this action . As a consequence they need relatively higher line pressures in order to get satisfactory braking performance.
This gives rise to the need for the booster.

This is not to say you could not run with out a booster but you will need to compensate in some other way to get the line pressures high enough and maintain a reasonable peddle pressure. A reduction in M/C bore diameter would help but you then have a reduced volume of brake fluid which results in greater (relative ) pedal travel. You could wind up running out of travel before the brakes are effectively applied.You don't want that.

Anyway you look at it you will need the high line pressure for the front discs and a means of limiting pressure to the rear drums otherwise they will lock up with only the slightest provocation.

 

Thanks fred for explaining it to me clearly. I'm convinced to go with a booster. Just adds one more thing on the list to buy/do.

Now, onto the next question. Does booster size matter?

 

Should I box the frame with an IFS?

 

Short answer yes.
The amount of boost is directly proportional to the area. Area is proportional to the square of the radius. This means if you were to double the diameter then, all else being equal you would have 4 times the boost. Conversley if you reduce the diameter by a half then you would have only 1/4 of the boost.

If the bulk of the booster is a problem then have a look at some of those twin diaphragm boosters that are available now.

The links below shows what some folks are offering out there. This is not a plug for SM btw.
http://www.speedwaymotors.com/ProductSummary.aspx?free_text|7/24/2010 6:56:26 PM=booster&deptId=0

http://www.rodandcustommagazine.com...ter_power_brakes_diagnostic_kit/photo_11.html

 

Looking at the build up on the link provided by Cymro, my inclination is to say yes.

The way the Jag front end is originally fitted to the Jags at the factory is to a box section as well .

 

I have jag front and rear in my Lincoln and have used the original jag dual booster. Very compatible obviously.

 

I dont know much about these but it may be worth checking out the engine powered brake boosters on diesel engined European and J** cars we are not supposed to mention here these work very well on the original cars / commercials such as the Mondeo, Focus etc, I don't know how these would adapt to heavier vehicles or their availability in the |USA, but I'm certain you have diesel powered cars and pick ups from which these parts can be pinched or adapted

 

I would just as soon have a smaller booster because I don't like that super light brake feel. Too sensitive. I want to feel what the brakes are doing.

Yesterday I pulled a clip from an '82 XJ6. Also got a heat stroke to boot. The parts are in decent shape, but are surface rusted and pitted a little. I'm wondering whether to powdercoat it or just slap POR15 on it.

 

I boxed the frame a bit both fore and aft of the front clip when I did my 57 Buick. And I run a MANUAL Corvette master cylinder with absolutely no problems.

 

Thanks for the suggestion. I did call Curt and got the following advice:

Use a large booster. I plan on a 8" double-tight fit under the floor

You will want about 2 1/4" from the centerline of the pedal pivot to the centerline of the attachment of the rod going into the booster. That is just about what the stock pedal dimension is.

Recommended a 1" diameter master cylinder piston size. I plan to check out a Corvette aftermarket

Note that this is for my 1949 F-1 Ford truck with the XJ-6 IFS and a 9 inch rear

 

I have installed one in a 49/50 F1 Pickup and have one installed in my 50 Chevy. I'm using a mid 80's camaro brake booster and the car will throw you through the windshield with the power of the brakes. The steering joint is available through Speedway.

 

Did you install the same size brake booster/master cylinder in both the F-1 and 50 chevy? I want some brake feel and not something real sensitive. Would you have considered backing off a bit on the booster size? I tried to find out what the booster size is on the stock mid 80's Camero. Is it a 9" dual?

 

I have an '85 xj6 suspension on my '57 Suburban and a manual Vette m/c and it stops great. The suburban has a big block in it and the suspension holds up just fine.