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Different viewpoints on brakes  Rating:  Rating
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 Posted: 09-04-2005 12:28 am
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Mark Rosenbaum
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Ran across the site below involving folks who put V8 engines into things such as Vauxhall Vivas.  Naturally they then need improved brakes, and some of them seem to have taken a completely different approach from the ones generally considered by JH folks.  Worth taking a look, especially the photo album one of the posters has.

http://v-8.org.uk/forum/topic.asp?TOPIC_ID=471&#12148

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 Posted: 09-04-2005 04:23 pm
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Judson Manning
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Mark,

Thanks for uncovering another option.  I actually was developing something similar to the V8 Viva guy's solution, but eventually abandoned the project.

The primise of my solution was in keeping with the stock JH wheels, which meant keeping the JH hub and spindle.  The challenge was to find a cost-effective rotor and caliper combination that would fit.

The rotor size is pretty much maxed out at 10", therefore, I used a Toyota Celica/Supra 10" vented rotor (the same as the early Esprit) found at my local auto parts store for ~$20.  Making an adapter plate wasn't too difficult, however, my machinist never got around to doing it (which is one of the reasons why I don't use him any more).

The challenge was finding a caliper that would fit inside the JH wheel and be a real improvement over the JH caliper.  I never found one that satisfied me.

For those cars that stick w/ the stock JH wheel for their limited track excursions, I think removing the dust shield, a switch to HP pads, and some brake ducting will be enough.  In Improved Touring, these are the only real legal options for Ron Earp, so we'll have to see how his car does.

Alternatively, if we ditch the idea of retaining the stock wheels, MANY more options are available.

Judson

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 Posted: 09-05-2005 01:51 pm
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Ron Earp
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Duct, duct, duct.  Did I say duct?

Improved Touring has LOTS of cars that have solid rotors and less than optimal brakes for severe race duty.  But, they can be made to work and work well.

For example, Datsun Z cars run in IT with solid discs, rear drums, and weigh in about 400lbs heavier than a JH with more motor to boot. With no care taken to lines, fluid, and ducting the brakes will be done in within two laps, no kidding.

But, with care to lines, using high boiling point fluid (550-600F) that is always fresh, race pads, and the big one - two ducts to each wheel, the brakes will last a 45 minute race with no fade which is a heck of a lot more stress than you can come up with doing any street or spirited driving on back roads.  You need one duct to the caliper itself and the other duct goes to the rotor hat.  A rotor hat is simply a metal tube with a slot cut in it where the rotor spins through and the tube is bolted somewhere convienent so it won't move around. A air tube is clamped to the hat and thus air is blown on both sides of the disc.

Ducts are easy to make, really work, and are cheaper than fitting aftermarket brakes, calipers, etc.  Right now I'm laid off my JH prep because I have a spec Miata to finish up, but once I'm back on it I'll finish the duct work and shoot some pictures in case anyone wants to duplicate them. 

Just duct it.

R

Last edited on 09-05-2005 01:53 pm by Ron Earp

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 Posted: 02-28-2008 12:27 am
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D.Drake
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    Judson
In 2005 you were working on a setup to rep[lace the original JH disc with 10" Celica  disks . Were you ever able to complete that project and if so are you happy with it ?

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 Posted: 02-28-2008 05:57 pm
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Joel
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Give Norm a shout.  I've seen his conversion (in pics) and it looks really nice. I think this is probably the way I'm going to go - if I can ever get around to STARTING my project.

http://www.jensenhealey.com/forums/view_topic.php?id=502&forum_id=6

I like the 4 disk brake idea.  I have to say that the brakes on my 74 are the one thing I am REALLY disappointed in.  I have stock brakes - new pads, turned rotors, etc.  And they SUCK!

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 Posted: 02-29-2008 10:26 am
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Judson Manning
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Everyone's 'milage' will differ...

To answer your question DDrake - No.  I never pursued the Celica rotor solution after my experience at the Gainesville, FL Solo I last year.

Running 8" slicks (and no rear brakes) the stock front calipers with Hawk pads held their own.  Yes, I did experience some brake fade in a competition environment, but again I had zero rear brakes.  Once I got the rears fixed, I really had no reason to complain.

The Hawk pads I was using were meant for the Formula Ford and actually smaller than the stock JH size (hard to find competition JH pads on the shelf!).  If I did some brake ducting up front and used the bigger pads, the fade certainly would have been less.  Not to mention the fronts were doing double duty.

Before anyone immediately throws out the stock set-up, keep in mind a number of  formula cars use our caliper and it is well proven in competition.  Tires are actually the most effective part of the braking system.  A good set of sticky 205s will go a long way to curing suspected braking issues (assuming all parts are actually working!).   Throw in some higher performance pads (Porterfield, Hawk, etc.) and fresh fluid running through the TR6 master cylinder and most people (even in a competition setting) should be pretty happy.

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 Posted: 02-29-2008 04:04 pm
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Greg Fletcher
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The stock set up is not bad if it's all working as it should. I remembered that they always seems good on my old car and I've just gotten my current JH on the road since I started my restoration and I would describe the brakes as completely adequate. My brake system is basically brand new; a fresh master cylinder, stainless steel brake hoses, Castrol GT LMA DOT 4 fluid, rear linings and drums that look they just came from the dealer, rotors with no wear to speak of, rebuilt calipers and the newer Lucas ceramic brake pads all contribute to that. I'm comparing this to a modern German car I drive everyday (that has astonishing braking power), so for a car that's 35 years old, the Jensen Healeys brakes are surprisingly good.

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 Posted: 02-29-2008 04:15 pm
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JodyFKerr
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Greg,

Quick question on the brake lines. Did you make your own, or is there a source that has them already bent and flared? As soon as my leg works I'll be reassembling the brakes on my project and the brake lines are either gone or in a crap state.

Thanks!

Jody

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 Posted: 02-29-2008 05:05 pm
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Joel
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Well maybe I just like to stop sooner than everyone else.  I have new master cylinder, new lines, new pads and shoes, new calipers, freshly turned drums, and I'm still not happy with the stopping power.  Sometimes it seems I can barely get them to lock up.  And they fade like hell if I'm really working them. 

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 Posted: 02-29-2008 06:57 pm
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Judson Manning
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Joel,

Prior to the Hawks and Porterfields I tried a set of pads from one of our well known sources and they just were terrible.  I could stand on the pedal with both feet and never get any action.  Just prior to swapping out your entire brake system, it might be worth a call to http://www.porterfield-brake.com

Judson

 

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 Posted: 02-29-2008 07:51 pm
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Greg Fletcher
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I'm sure some quality brake pads would make a world of difference on this car.

Jody- I have the SS flexible brake hoses (I don't have any SS rigid lines for the stock system) custom made in the USA by a well respected company, but there are others available as well. The original rubber hoses were fine, but those are NLA and have been replaced by shorter, Chinese made rubber ones that I found to be poor quality and not long enough. Just changing a hose in and of itself will not realize a burst of improvement. Like many things, it's an incremental change for the better.

Joel- the JH brakes should not "lock up", the system is not designed to work that way. You should have a solid, progress stop. Does your brake pedal feel rock solid all the time, or do you have some play in the pedal as your braking?

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 Posted: 03-01-2008 12:18 am
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Joel
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I've slowly gone thru the entire system and replaced EVERYTHING as outlined in my previous posts.  I think the brakes feel really weak.  There's plenty of height to the pedal, it feels firm.  But, when push comes to shove (or to errr...stop...), I feel like my foot is all the way into the brake and there's no more stopping power.

I'm not sure why brakes with no ABS wouldn't lock up at a full stomp from 20mph or more. 

And because I don't have much confidence in the brakes I haven't didn't work them so hard on my recent romp - good practice actually but that's a different topic. I was racing with an Austin Healey around the mountains and I didn't have the luxury of heating the brakes and having to ease up on my driving - or he would have passed me - it was a built Austin and he was a good driver! So I drove moderately hard instead of laying on the brakes later into the corners.  Yet I digress...

Anyway, I didn't hammer on the brakes too much the last trip but they also seem to fade very quickly when I'm pretending to be Mario Andretti. 

I'll spring for some pads from Porter and see what happens.  I think there is info on part #'s etc from another post so I'll go search for that. 

And thinking about it - pads might make sense because when I first put the new pads and shoes on it I was pretty happy.  Maybe they're getting progressively worse - it's only been a couple hundred miles so maybe they were better before. 

Judson - did you see my post regarding my shifting troubles? Whaddya think? Throwout bearing, clutch cable, something else?  I don't think it's the tranny itself...


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 Posted: 03-01-2008 02:29 pm
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Jensen Healey
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The Hawk pads for the Spitfire drop right in and are a great improvement.

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 Posted: 03-03-2008 11:31 pm
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Joel
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Ok just got off the phone w/ Porter-field.  Should have new pads shortly! R4S compound.  A little over 200 bucks all the way around.  I do have to send them the rear shoes. 

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 Posted: 03-04-2008 12:35 am
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D.Drake
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Judson
That sounds like a good workout for the front brakes ! I am generally pretty frugal but I am not against using the rear brakes pads when needed ;-)
What I was actually try to find was a more readily available front rotor replacement .I hadn't considered going 4 wheel disks

Last edited on 03-04-2008 12:36 am by D.Drake

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 Posted: 03-29-2009 06:18 am
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carl.bedlington
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I am very interseted in the brake ducting modificatiion. Do you or anyone have and photos, drawings or information on how to go about this.

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 Posted: 03-29-2009 09:13 pm
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Jensenman
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I have Ron's IT car which has the ducting installed on the J-H brake setup. I plan to remove the ducting and adapt it to the Miata brake stuff I am using but I'll take some pics before I disassemble it and post them in the 'Projects' section.

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