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Brake recommendation??
- Thread starter wlivesey
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stevebn2bj7
Jedi Warrior
Offline
As I see it there are two options. One is to update to the Mark 2/3 power brake booster with its larger master cylinder and brake booster. The other is to change the rear brakes to disc using one of the available conversion kits. I have updated the rear on my BJ7 to discs and am very happy with the stopping ability of the setup.
Offline
Hi Bill,
It all depends on what you want the brakes to do. If you are racing & going from 120 to 35 mph, lap after lap, there might be an advantage to the greater cooling ability of rear discs.
A booster does not increase braking ability, just reduces pedal effort.
If you are not using them this hard, the rear drums offer just as much stopping ability as discs, until they get really hot.
There are a number of high friction lining compounds that can greatly increase stopping ability, from cold to very hot. A typical "very good" lining compound such as Porterfield R4S or R4, will greatly increase braking power with less pedal effort. If you need stopping with cold brakes, the R4S works better. There are similar compounds available from other manufacturers.
Folks in some vintage race classes are not allowed to change from drum to disc, but they get by very well with high performance brake lining.
https://www.porterfield-brakes.com/
D
It all depends on what you want the brakes to do. If you are racing & going from 120 to 35 mph, lap after lap, there might be an advantage to the greater cooling ability of rear discs.
A booster does not increase braking ability, just reduces pedal effort.
If you are not using them this hard, the rear drums offer just as much stopping ability as discs, until they get really hot.
There are a number of high friction lining compounds that can greatly increase stopping ability, from cold to very hot. A typical "very good" lining compound such as Porterfield R4S or R4, will greatly increase braking power with less pedal effort. If you need stopping with cold brakes, the R4S works better. There are similar compounds available from other manufacturers.
Folks in some vintage race classes are not allowed to change from drum to disc, but they get by very well with high performance brake lining.
https://www.porterfield-brakes.com/
D
Just because it looked interesting, here is an article about a guy that converted his TR4 to the four piston Toyota 4X4 calipers. this is also a recomendation for Datsun 240Z's also and looks like it might be a viable conversion for our Healeys. Better stopping, more friction area, and an inexpensive upgrade fro the front. Just FYI.
https://www.vtr.org/maintain/brake-conversion.shtml
No interest and I haven't had the opportunity to see how different the Heaely caliper is from the TR...
Dave Duffey
59 BT7 project
Paradise, CA
https://www.vtr.org/maintain/brake-conversion.shtml
No interest and I haven't had the opportunity to see how different the Heaely caliper is from the TR...
Dave Duffey
59 BT7 project
Paradise, CA
JamesWilson
Yoda
Offline
[ QUOTE ]
...looks like it might be a viable conversion for our Healeys.
[/ QUOTE ]
I've not finished it yet but it certainly seems to be. My car is still having major welding done to the chassis and inner body but I've sourced a number of the suspension and brake components and I've done a fair bit towards installing this set up.
The story so far:
Magnus Karlson on Larry Varley's site discusses an upgrade based on using Volvo four piston calipers. These seem quite hard to find, and involve substantial modifications in their fitting. A more straight-foward uprating seemed to be one using Toyota calipers as described for a Triumph at www.vtr.org/maintain/brake-conversion.html that describes the conversion well for a TR.
The parts needed and the relevant Toyota references are:
Left Caliper: Toyota P/N 47730-35080
Right Caliper: Toyota P/N 47750-35080
Pads: I bought these through an after-market supplier and do not have the Toyota P/N
Shims, springs and pins will be needed unless you get a fully kitted out caliper, and the source I found wasn't able to supply such a thing. One of the calipers came with pins, one did not. There are two types of shims- plain and "vented" , the vented go next to the pad, the plain against the caliper. The springs go across the caliper to tension the pads, and a retaining clip goes between the pins. The required information:
Shims 1: Toyota P/N 47744 (set of 4)
Shims 2: Toyota P/N 47745 (set of 4)
Springs 1: Toyota P/N 47748 (set of 2)
Retaining Clips 2: Toyota P/N 47748A (set of 2)
Pins: Toyota P/N 47748B (not sure about the "B" , the copy was not as good as it could have been, the P/N is for one)
These do not appear to be readily available from anyone but Toyota in the UK. Its also possible to obtain a kit comprising all the shims and tensioning springs that is a little cheaper than buying them individually. These seems to be far more readily available and much cheaper in the US than in the UK- I've seen a number for sale on e-bay; but thought it better to find a UK source where I could take the various bits in and see how they all lined up.
The vtr reference describes the source vehicle as Toyota gasoline powered pick-ups 1979-1983, my vendor listed these as coming from Toyota Hi-Lux pickups 89-97 and Toyota 4 Runners from 1993 on.
Hardware- in order to mount the calipers a little tinkering is necessary. The calipers come with metric mounting holes, the Healey stub axles have imperial threads. A hybrid bolt is available that has a 12mm shaft to fit the caliper and 7/16 UNF threads to fit the stub axle. This was used on very late model TR6s. It is available from Rimmer Brothers www.rimmerbros.co.uk, and the relevant part number is: 158668 - It is listed under TR6 brakes as the mounting bolts for the Girling type M16P caliper. The cost was ÂŁ3.87 each. (ouch!)
Fitting issues:
1) The Healey back plate needs trimming so that the larger Toyota caliper will fit. The clearance provided the old caliper was used to jdge how much needed to be removed to allow the new one to fit. Tin snips were used to remove the material.
2) The old hard brake line from the caliper to the bracket/flexible line needed to be replaced with one fabricated to match the new caliper's metric inlet and the old flexible line's imperial fitting.
First Caveat: a trial fit of the bolts showed that they are almost right for the Healey. They confirm that the bolt holes line up properly and that the centerlines of the Toyota and Healey calipers are identical. The problem is that the threads on the bolts are 1/4 inch too short, and the bolt heads protrude that far towards the disk surface, and the caliper would not be tightly attached to the stub axle. The thickness of the bolt makes it impossible to easily cut threads beyond those already there, and I suspect that I may have to try and have that section of the bolt cut down by someone with a lathe. Alternatively, I may get some 12 mm copper tubing and fabricate some bushings to allow the original bolts to be used- or see if I can get some bolts machined to fit. When I do get around to mounting the suspension and brakes I'll bite the bullet and fix tis problem but until then its something I've just put aside.
Second Caveat: The Toyota Disk is 20 mm, the Healey one 1/2 inch. There is thus a difference of ~7.3 mm that will require the pistons to extend beyond where they normally might do (I haven't investigated the minimum thickness allowed for Toyotas). The concern is that some greater or lesser amount of wear will combine with this extra extension required of the calipers and might, at some point, cause the pistons to over-extend with a consequential loss of fluid and possibly pressure. No brakes. My response to this possibility was to first contact the Vintage Triumph Register article's author. He found there was no problem during the time he'd used the car. But I suspect that as a racer he paid a lot of attention to the brakes and pads, and the pads may have been replaced more frequently. My intention is to use an additional set of shims to take up the gap. I have 1/8 inch thick flat steel that will be fabricated into shims matching the outline of the plain ones from Toyota. These will take up 3.175 mm of the 3.65 mm gaps on each side of the disk. The resulting shortfall would then be less than 1 mm, and I am more comfortable with that. Using 4 mm steel for a fabricated shim and deleting the Toyota supplied plain one would also have been a workable option- and I suspect it would have more closely made up the difference.
I've looked for a ventilated disk that might fit but have been singularly unsuccessful in that. Someone's suggested that one from another model Toyota would fit, but a quick compariison of its from Brembo's site shows its no where near close. I've considered seeing if any of the aftermarket suppliers of 4-pot brakes have anything that might work, but I'd want to go in and lay everything together and make absolutely sure it all lines up and fits. Again, maybe that's a chore for later in the project. But the stock disks seem to be entirely suitable.
Statistics:
Stock Healey: Piston size: 2 inch, Pad area: 4.25 sq inches.
Toyota: Piston size: 2 x 1.5 inches, Pad area: ~7.4 sq inches,
The Toyota Piston area is virtually identical to that of the Healey ~ 1.5% larger while the pad area is much greater ~3/4 larger.
Weight: both are iron and seem to weigh about the same.
I can't yet say how well they work (or even if they will work) but I've done a trial fit and it all hangs together quite nicely.
If anyone has finished the job I'd be very interested....
...looks like it might be a viable conversion for our Healeys.
[/ QUOTE ]
I've not finished it yet but it certainly seems to be. My car is still having major welding done to the chassis and inner body but I've sourced a number of the suspension and brake components and I've done a fair bit towards installing this set up.
The story so far:
Magnus Karlson on Larry Varley's site discusses an upgrade based on using Volvo four piston calipers. These seem quite hard to find, and involve substantial modifications in their fitting. A more straight-foward uprating seemed to be one using Toyota calipers as described for a Triumph at www.vtr.org/maintain/brake-conversion.html that describes the conversion well for a TR.
The parts needed and the relevant Toyota references are:
Left Caliper: Toyota P/N 47730-35080
Right Caliper: Toyota P/N 47750-35080
Pads: I bought these through an after-market supplier and do not have the Toyota P/N
Shims, springs and pins will be needed unless you get a fully kitted out caliper, and the source I found wasn't able to supply such a thing. One of the calipers came with pins, one did not. There are two types of shims- plain and "vented" , the vented go next to the pad, the plain against the caliper. The springs go across the caliper to tension the pads, and a retaining clip goes between the pins. The required information:
Shims 1: Toyota P/N 47744 (set of 4)
Shims 2: Toyota P/N 47745 (set of 4)
Springs 1: Toyota P/N 47748 (set of 2)
Retaining Clips 2: Toyota P/N 47748A (set of 2)
Pins: Toyota P/N 47748B (not sure about the "B" , the copy was not as good as it could have been, the P/N is for one)
These do not appear to be readily available from anyone but Toyota in the UK. Its also possible to obtain a kit comprising all the shims and tensioning springs that is a little cheaper than buying them individually. These seems to be far more readily available and much cheaper in the US than in the UK- I've seen a number for sale on e-bay; but thought it better to find a UK source where I could take the various bits in and see how they all lined up.
The vtr reference describes the source vehicle as Toyota gasoline powered pick-ups 1979-1983, my vendor listed these as coming from Toyota Hi-Lux pickups 89-97 and Toyota 4 Runners from 1993 on.
Hardware- in order to mount the calipers a little tinkering is necessary. The calipers come with metric mounting holes, the Healey stub axles have imperial threads. A hybrid bolt is available that has a 12mm shaft to fit the caliper and 7/16 UNF threads to fit the stub axle. This was used on very late model TR6s. It is available from Rimmer Brothers www.rimmerbros.co.uk, and the relevant part number is: 158668 - It is listed under TR6 brakes as the mounting bolts for the Girling type M16P caliper. The cost was ÂŁ3.87 each. (ouch!)
Fitting issues:
1) The Healey back plate needs trimming so that the larger Toyota caliper will fit. The clearance provided the old caliper was used to jdge how much needed to be removed to allow the new one to fit. Tin snips were used to remove the material.
2) The old hard brake line from the caliper to the bracket/flexible line needed to be replaced with one fabricated to match the new caliper's metric inlet and the old flexible line's imperial fitting.
First Caveat: a trial fit of the bolts showed that they are almost right for the Healey. They confirm that the bolt holes line up properly and that the centerlines of the Toyota and Healey calipers are identical. The problem is that the threads on the bolts are 1/4 inch too short, and the bolt heads protrude that far towards the disk surface, and the caliper would not be tightly attached to the stub axle. The thickness of the bolt makes it impossible to easily cut threads beyond those already there, and I suspect that I may have to try and have that section of the bolt cut down by someone with a lathe. Alternatively, I may get some 12 mm copper tubing and fabricate some bushings to allow the original bolts to be used- or see if I can get some bolts machined to fit. When I do get around to mounting the suspension and brakes I'll bite the bullet and fix tis problem but until then its something I've just put aside.
Second Caveat: The Toyota Disk is 20 mm, the Healey one 1/2 inch. There is thus a difference of ~7.3 mm that will require the pistons to extend beyond where they normally might do (I haven't investigated the minimum thickness allowed for Toyotas). The concern is that some greater or lesser amount of wear will combine with this extra extension required of the calipers and might, at some point, cause the pistons to over-extend with a consequential loss of fluid and possibly pressure. No brakes. My response to this possibility was to first contact the Vintage Triumph Register article's author. He found there was no problem during the time he'd used the car. But I suspect that as a racer he paid a lot of attention to the brakes and pads, and the pads may have been replaced more frequently. My intention is to use an additional set of shims to take up the gap. I have 1/8 inch thick flat steel that will be fabricated into shims matching the outline of the plain ones from Toyota. These will take up 3.175 mm of the 3.65 mm gaps on each side of the disk. The resulting shortfall would then be less than 1 mm, and I am more comfortable with that. Using 4 mm steel for a fabricated shim and deleting the Toyota supplied plain one would also have been a workable option- and I suspect it would have more closely made up the difference.
I've looked for a ventilated disk that might fit but have been singularly unsuccessful in that. Someone's suggested that one from another model Toyota would fit, but a quick compariison of its from Brembo's site shows its no where near close. I've considered seeing if any of the aftermarket suppliers of 4-pot brakes have anything that might work, but I'd want to go in and lay everything together and make absolutely sure it all lines up and fits. Again, maybe that's a chore for later in the project. But the stock disks seem to be entirely suitable.
Statistics:
Stock Healey: Piston size: 2 inch, Pad area: 4.25 sq inches.
Toyota: Piston size: 2 x 1.5 inches, Pad area: ~7.4 sq inches,
The Toyota Piston area is virtually identical to that of the Healey ~ 1.5% larger while the pad area is much greater ~3/4 larger.
Weight: both are iron and seem to weigh about the same.
I can't yet say how well they work (or even if they will work) but I've done a trial fit and it all hangs together quite nicely.
If anyone has finished the job I'd be very interested....
bighly
Jedi Knight
Offline
Bill,
Check out the Dennis Welch setup. Both an uprated front system and an disk conversion for rear. A dual circuit system with adjustable balance is also available. Depends upon how quickly, how often and for how long you need to stop. As Dave mentioned, a better lining alone will make a difference unless you intend to drive with hot brakes (read race). If want to get really serious and have the bucks the DW setup should make a huge difference. My well maintained 1960 BT7 stock setup works great for my driving habits which include periodic spirited driving for extended periods.
Dennis Welch web page
Check out the Dennis Welch setup. Both an uprated front system and an disk conversion for rear. A dual circuit system with adjustable balance is also available. Depends upon how quickly, how often and for how long you need to stop. As Dave mentioned, a better lining alone will make a difference unless you intend to drive with hot brakes (read race). If want to get really serious and have the bucks the DW setup should make a huge difference. My well maintained 1960 BT7 stock setup works great for my driving habits which include periodic spirited driving for extended periods.
Dennis Welch web page
Here's another version of the early brake system that Magnus wrote about.
https://www.cardomain.com/ride/2247236/2
https://www.cardomain.com/ride/2247236/2