Front Brakes Dragging (need to bleed?)

Hi All,

2005 ABS model, 25,000 miles, new to me.

I have discovered (after investigating crappy mpg) that my front brakes are dragging. When I put it up and give the wheel a spin I get about 1/4 turn. I removed pads (came right out with a little shimmying), and calipers, but left the lines on. All pisons move easy-ish (rubber coated end of channel locks did the trick). Cleaned up the pads, and still dragging. Could it be air? The brakes are stopping ok and aren't too spongy, but I have to say that when I really get on the front, I don't get an amazing jolt like I am used to on other bikes. There is no "snap" in the brakes in other words.

I can't find anywhere that has instructions on bleeding just the front brakes, just the whole system, which I would rather not do. Rear wheel spins fine by the way. Any tips? Also, I have read about the 'return valve' possibly being blocked - where is this? Could that be the issue? Can the front brakes be bled alone or does the whole system need to be done?

Thanks - ps, I'm mechanically handy enough, but new to the VFR combined brake system, and dealing with lack of tools, parts and the rest in Ireland! Where is NAPA and Autozone when you need them... not here!

 

1. Did you lubricate the caliper slider pins? If they are dry and sticking, that's probably what's causing the dragging. If you didn't already, try lubricating the caliper pins before bleeding the brakes.

2. You can bleed just the lines attached to the front master cylinder (which go only to the front calipers). The front master cylinder operates five of the six front pistons (three on the right, two on the left). The procedure is the same as any conventional non-linked braking system. Things only get more challenging when you are working with the rear master cylinder (this is when you have to remove and position the calipers).

 

I didn't lubricate them, as I know some lubricants are dodgy with brakes. Any recommendations?

 

Which pins are we talking about? I have attached a schematic. Number 11, 16 or both? It also looks like there is a pin on assembly 19?

 

1/4 turn is pretty tight! Any chance you have the wrong pads installed?

The pins referenced above are shown as part of the assembly in 19 and 3 in the drawing. They should have a clean and lube once a season IMHO.

Bleeding the system or just the front is always a good idea as it flushed out the old contaminated fluid and loosens up any crap that may be in there as well as removing moisture from the system. This may help you but since you say that the pistons already move freely I'm a bit doubtful. That said, it's probably due for a flush being a 2005.

 

Thanks,

The pads are definitely the right ones. How much resistance should the slider pins have? They move smoothly, but with a decent amount of resistance. When hand pressure is applied, they move end to end in a second or two. They are 'tight', like caliper pistons, but not nearly as tight as that. What I am saying is that a fair amount of force is required. They are not by any means 'loose'.

When I took the pads out and replaced them after cleaning, the wheel spun freely, but once the front brake was applied the pads stayed tight immediately. Also, the brake lever was very loose after removing and replacing the pads, but a few pumps and it was back to feeling normal. Is that normal?

Project tonight is to identify if it is one caliper or both that is dragging. Would it mean anything significant either way (if it was just one, or if it was both)?

These things are wrecking my head!

 

As far as which grease, many automotive shops have "bake assembly" grease which is high temp stuff and sometimes can be found in little packets for ~$1.00 (think size of a ketchup packet), this is what I use to lube those pins. As far as the "hole" in the reservoir, I believe this is what to look for...

 

Look for sludge in the master cylinders. This is a good indication that the return valving needs a rebuild.

This from an almost finished rebuild of the front and rear master cylinders on the mach 1 91. Kits at Bike Bandit aboot thirty pesos each.

On the proportional systems not a clue but on the non-proportional either wheel can lock up if this condition exits. Bad shit follows. If this happens on the road, bleed off some fluid and do not touch the offending brake lever until you get home or to a shop.

 

Oddly, on my Duc, after I changed the tire and put the wheel back on, the brakes were dragging very heavily, I thought I had put the wheel on incorrectly but after removing and reinstalling and verifying everything was on correctly, I pulled the calipers apart and gave them a thorough cleaning/lubing and put it all back together and all was good after that. Personally I think it might be worth doing but you would have to do the entire brake bleeding procedure if you went that route. Good luck.

 

OOTV - Thanks. I'll check that return valve, and hopefully won't have to bleed all.
Badbilly - Will do - I'm gonna open the master cylinder tonight.

 

I had the same problem on one of my VFRs.
Had to take the front calipers apart and give them a good cleaning paying particular attention to the pistons
Now everything is A-OK

 

The caliper should move smoothly on the caliper pins without binding. There might be a slight bit of resistance, but it should be very smooth. They should definitely be lubricated, at least with every brake pad change. Use any clear silicone brake caliper grease. I use a Ford/Mazda brake caliper/dielectric grease, but there are plenty of brands.

When the caliper was reinstalled, the brake lever had to be pumped several times to push fluid into the caliper to push the pistons back into contact with the pads. This is normal.

 

Thanks everyone - bit of an update here. I took everything apart again and found some corrosion/rust issues with the pads. The pads that are not on the piston side of the calipers have a metal 'cage' sort of thing on them, and the pad backing plate had corroded underneath, to the point of blistering and actually increasing the thickness of the pads overall - perhaps as much as 1/8 inch. I removed all this crap with a big flat screwdriver and wire-brushed the hell out of them. After replacing and pumping the brakes, they were still dragging, but a little shaking of the calipers results in the wheel spinning pretty good.

Question is - when I go for a spin in the AM, will heat, and just driving, be enough to move the calipers around enough that the brakes won't drag under normal use?

I'll report back!

Thanks again.

 

The tiny return orifice is clogged

It is located under the round metal tab.