Front Calipers - Disassemble or not?

[Cutlass]

Before disassembly of my 66 BJ8, the front brakes were apparently working fine, though the calipers are rusty and dirty. I've disassembled calipers before, installed new seals, etc. with no problem, but I seem to remember advice to the contrary unless there is a known problem. But proper cleaning and inspection demands disassembly and reassembly, which seems pretty straightforward. Any overriding reason not to do this myself?

 

[shorn]

From what I remember, you must have the proper size o ring for reassembly, otherwise the seal isn't good. I believe they are available.

 

[John Loftus]

Cutlass,

Rebuilding the calipers is pretty staight forward. Most replace the chrome plated pistons with stainless steel. The factory stated that the calipers should not be split .. probably a liability concern but many have been split to completely rebuild the units and replace the rubber square profile O ring between the halves. The O ring, pistons and rebuild kits are available. (I've heard the O ring is avail through Moss Motors in the TR6 catalog as item #583-820). I purchased all my parts through John Farell at https://www.fortunecity.com/silverstone/tread/1046/id23.htm

There was a similar thread last week on calipers ..
caliper rebuild thread

Cheers,
John

 

[Ed Kaler]

[ QUOTE ]
The factory stated that the calipers should not be split .. probably a liability concern but many have been split to completely rebuild the units

[/ QUOTE ]

Yes and no, John (Hi BTW!!) /ubbthreads/images/graemlins/angel.gif

The IS (and I cannot find my copy after moving my office after 15 years /ubbthreads/images/graemlins/hammer.gif)A Service Tech Bullitin which states that only NEW bolts s/b used when "splitting" as the originals' have been stretched and re-torquing would stretch them further. /ubbthreads/images/graemlins/frown.gif

/ubbthreads/images/graemlins/cheers.gif
Ed /ubbthreads/images/graemlins/savewave.gif

 

[Keoke]

/ubbthreads/images/graemlins/savewave.gif
Prolly some good advice ED ,but lacking the service bulletin, I doubt that many of us were that smart when we rebuilt the calipers.---Keoke- /ubbthreads/images/graemlins/thumbsup.gif

 

[Cutlass]

Upon cleaning the still assembled calipers today, I discovered that one had been cracked and repaired by brazing where the threads of the smaller bolt are. Glad I at least cleaned it. Now to find a rebuildable caliper. Also, the larger bolts are not cooperating in coming out. they are now soaking up the penetrant for a day or two. The pistons appear new, but are not moving. I guess that this is part of what makes the hobby interesting, solving problems you didn't know existed yesterday. On a more positive note, I did get to watch the chassis being painted Friday. That shiny Healey Blue sure does show up all imperfections. Good thing that the sheet metal and interior will cover most of them up.

 

[Keoke]

Yes, the HLY is very bashful about showing up her faults. Glad you saw the old problem before it can become a new one.If whatever solvent you are using on the bolts does not work,get some PB Blaster and soak em a bit and follow their instructions.---Keoke- /ubbthreads/images/graemlins/yesnod.gif

 

[Cutlass]

PB blaster is what I'm using. I hit them periodically with an impact wrench to shake things up. One warning on the sticky pistons: I put air pressure on one side, and sure enough both pistons started moving. One came out with a pop, but not the other. I covered up the fluid hole on the now empty cylinder and started the process again. It worked also, but the second piston came out like a shot, and, of course, blasted my finger. Ouch! Luckily noting but a bruise. Good news is that the pistons are pristine, as are the bores. Now if I can just get the bolts out.

 

[John Loftus]

[ QUOTE ]
A Service Tech Bullitin which states that only NEW bolts s/b used when "splitting" as the originals' have been stretched and re-torquing would stretch them further.


[/ QUOTE ]

Hi Ed! /ubbthreads/images/graemlins/savewave.gif

Ah yes .. now I recall someone bringing this up before .. probably you! Haven't heard of any problems with rebuilt caliper bolts failing .. wonder what Apple, White Post, Hendrix, BCS and the rest do when they rebuild calipers? Are new bolts available?

Cheers,
John

 

[John Loftus]

[ QUOTE ]
Now if I can just get the bolts out.

[/ QUOTE ]

Hi Cutlass,

Tried a 3 foot breaker bar with a 6 sided socket yet?

Cheers,
John

 

[Keoke]

[ QUOTE ]
[ QUOTE ]
A Service Tech Bullitin which states that only NEW bolts s/b used when "splitting" as the originals' have been stretched and re-torquing would stretch them further.


[/ QUOTE ]

Hi Ed! /ubbthreads/images/graemlins/savewave.gif

Ah yes .. now I recall someone bringing this up before .. probably you! Haven't heard of any problems with rebuilt caliper bolts failing .. wonder what Apple, White Post, Hendrix, BCS and the rest do when they rebuild calipers? Are new bolts available?

Cheers,

John

[/ QUOTE ] HI John, I was thinling the same thing about the rebuilders when I made the earlier post. I Think John Farrell can get the bolts, The SS Piston guy, or knows where to get them.---Fwiw--Keoke

 

[Cutlass]

Haven't tried the three foot breaker yet. Just my regular 18" or so breaker. Patience and working up the ladder is the key here. The last think I want to do is break off that bolt. That being said, just what is the recommended torque for these buggers? And one more thing, as I said, the pistons are pristine, which is unusual, so I thought that they might be stainless. My usual test using a magnet showed that they were magnetic, but is there another way to tell? There are no markings on them.

 

[Keoke]

HI Cutlass, the magnet test is good if you can sense the difference in pull between a steel one and a SS one. Both will show some magnetic properties with the SS one being the lower of the two.---Fwiw--Keoke

 

[Cutlass]

I think I've just got some new pistons that the prior owner had installed about three years ago, and for some reason, they have lasted. They may be hard chromed.

 

[John Loftus]

[ QUOTE ]
what is the recommended torque for these buggers?

[/ QUOTE ]

Hi Cutlass,

The 3 foot breaker bar was an exaggeration .. an 18" bar should break it loose but I agree on approaching the "problem" with patience. Also, I'm not surprised that chrome piston are still looking pristine after only three years. It takes a long time to get to pitted, rusty, flaking chrome pistons. Mine were in there for about 45 years and didn't look all that bad.

I wrote to John Farrell and he said that he did not think the replacement bolts were avail. He said they were a special bolt with a slight difference in pitch on the threads to act as a locking bolt (maybe that's why they are difficult to remove!). He recommended using a good quality locktite on the threads and torque to about 38 ft/lbs. He said he has never had any problems with the calipers in the 30 years he has been doing it this way.

Cheers,
John

 

[Cutlass]

Thanks for the info. I'm hitting the bolts with the impact wrench with a six point socket a few times to giggle the penetrant in, then letting it sit for a day or so, then repeat. Might apply a little heat from a propane torch for good measure, not enough to melt the seals, though. I'm picking up the newly painted chassis Friday, so I'm pumped. Probably only a couple of years left to go, now.