TR4/4A TR4A Brake Pads

[habaneronut]

Well, I've read my manual and looked through the archives, still can't find an answer so I come again to the experts.

I've just found out I've got TR4A brakes on my 3A while trying to install those brake silencer shim to quiet a persistent squeal. I've got the "C" caliper described by Moss as evidenced by the retaining pins with cotter pin fasteners. Hard to tell from the pictures in the Moss catalog, but I think the pads may actually be for the "B" type caliper rather than the "C". They were EXTREMELY hard to remove, had to use vise grips, and even then the inner pad took about five minutes of wiggling to break free.

Once the pads were out, the pistons moved forward enough that there is no way I am going to get the pads back in without some kind of adjustment, even without the new shims. The manual says to push the pistons back to their full extent of travel, but they just don't move. Would opening the bleed nipple a little help, or is it just that some #$@$$6% PO put on the wrong set of pads?

Fred

 

[Geo Hahn]

I would try cracking open the bleed screw... your system may have a 'restrictor valve' (a vertical thing about 1.5" long atop the 4-way connector that also has the brake light switch) that makes it hard to push backwards.

I use an old piece of aluminum bar stock (actually a side curtain support from an old cheesy JCWhitney side curtain) to lever the piston back. Clean well around the boot with a tooth brush (your wife's not yours) so you don't trap a lot of dirt & dust in the boot as it folds back.

 

[TR3driver]

Hard to tell from the pictures in the Moss catalog, but I think the pads may actually be for the "B" type caliper rather than the "C".

The C pads have holes for the pins, and no locating tabs. The A and B pads have locating tabs but no holes.

Once the pads were out, the pistons moved forward enough that there is no way I am going to get the pads back in without some kind of adjustment, even without the new shims. The manual says to push the pistons back to their full extent of travel, but they just don't move. Would opening the bleed nipple a little help,

Certainly try opening the bleed nipple. As Geo mentions, there is a residual pressure valve that is supposed to hold the pistons out; and maybe you can't get enough force against the pistons to overcome the valve. I took the guts of my RP valve out a long time ago, so maybe I've forgotten, but I don't think it should take excessive force to overcome the valve.

Another possibility is that your MC is not returning far enough to open the "foot" valve that allows fluid to flow backwards through the MC and into the reservoir. Could be the MC pushrod isn't adjusted right; or the pedal return spring is missing; or the pedal pivot is binding.

If opening the nipple doesn't help, then I think a caliper rebuild is in order.

 

[habaneronut]

Things just aren't ever simple with these LBC's are they? I guess that's why we love em so much! They wouldn't be near the fun if we got to drive them more then about 30 days a year, what with weather and mechanical problems conspiring against us.

Thanks for the suggestions, guys, looks like I have plenty to check tomorrow afternoon. Will let you know how it comes out.

Fred

 

[MichaelG]

I have a 4A with the aluminum shims, and I still have some brake squeal. Planning to use either an antisqueal stick on pad or some other product as well.

What have others used for this problem

Thx

MG

 

[habaneronut]

Looks like rebuild it is, Randall. Got back to it today and cracked the bleed nipple, cracked it a little more, and finally just took it out. Not a drop, and a C clamp tightened against the outer piston doesn't even budge it. After a closer look at the inner piston, it is really all corroded inside and I don't believe it has even been moving.

What all is involved in a rebuild, remember I'm a complete mechanical neophyte? Seems like I've seen some rebuilt or new calipers in one of the catalogs - would I be better off just getting them? If so, do they come with the pads and pistons and all, or just the caliper housing itself?

Haven't even looked at the other side, but bet I've got exacly the same problem there.

Fred

 

[TR3driver]

What all is involved in a rebuild, remember I'm a complete mechanical neophyte? Seems like I've seen some rebuilt or new calipers in one of the catalogs - would I be better off just getting them?

Rebuilding them can be a challenge; but really the only hard part is getting the old pistons out if they are badly stuck. In your case, it might be better to let someone else fight the battle.

But the basic procedure is to remove the pistons & dust covers, then pry out the seals. There is a long-running debate on whether to separate the two caliper halves or not; the official advice from Girling (and Triumph) was to never separate them. But there is another seal (O-ring) between the caliper halves that IMO should be replaced if there is any chance it has been contaminated with solvent or incorrect brake fluid. The O-ring is not included in the rebuild kit, but is available from the usual suspects.

The exact procedure (and which rebuild kit you need !) depends on whether you have the early "C" calipers or the later ones (used on some TR6). But basically you just put the main seal into it's groove, then install the piston & dust boot. On the earlier design, the dust boot fits into a second groove in the bore, so you have to struggle with installing one end of the boot over the piston, the other end of the boot into the bore, and then sliding the piston into the bore blind. The later design has the boot clamped on from the outside, so it's easier to assemble.

If so, do they come with the pads and pistons and all, or just the caliper housing itself?

I think they come without pads (since the pads should be a set and you may be replacing only one caliper); but should definitely include the pistons, locating pins (for the late calipers), bleed screws and so on.

BTW, it turns out that the rear brakes on my latest Triumph were totally stuck when I bought the car. Apparently the previous owner had never noticed. Worst part is, they decided to apply themselves while I was still over 1000 miles from home; and refused to release without a roadside tech session (actually a Wal-Mart parking lot). Fortunately for me, Wal-Mart was able to supply a BFH (etc) so we were able to continue without benefit of rear brakes /bcforum/images/%%GRAEMLIN_URL%%/smile.gif

 

[Andrew Mace]

Fred, you might well be better off getting rebuilts. Check around in your area amongst local parts stores and see if anyone can get rebuilts for you. Going online to partsamerica.com shows some pretty decent deals for a TR4A (nothing from AutoZone or NAPA, though).

 

[martx-5]

If you can get both pistons out, you should be able to rebuild the calipers without a problem. All of the parts are available, including the pistons. However, the pistons aren't so cheap, and from the sound of things, you are going to need some pistons. The other alternative is to send the calipers to someone like Apple Hydraulics and have them rebuilt. They may even have a set in stock they can send you, and then you just send the cores back for a credit.

 

[Geo Hahn]

...I still have some brake squeal. Planning to use either an antisqueal stick on pad or some other product as well. What have others used for this problem

I used a blue goo that comes in a little packet and spreads on. Works okay except (after a couple of years) I've been noticing some occasional squeal (possibly due to the very hot dry weather).

 

[habaneronut]

After seeing the prices in partsamerica(thanks Andy) I'm sure tempted to just buy these generic replacements. I'm certainly no purist, just want the car to look and run good since it's a daily driver (sort of - when it's running and the sun is shining).

They're selling CarDone rebuilt calipers with semi-metallic pad for $85.99 with a lifetime warranty. Anyone know anything/have any experience with these? They are selling them through Advance Auto, which just happened to open a new store in my town a few months ago.

Fred

 

[martx-5]

Cardone is a full line auto parts remanufacturer that has been in busisness longer then I've been in remanufacturing...which is over 30 years. I wouldn't hesitate to use there product.