|Tech Tips -- Product Review|
'Bolters helping 'Bolters is a beautiful thing!
Tired of asking folks to help you bleed brakes cause all those other "wonder tools" DON'T WORK?? You're in luck!! Irwin sez this one's GOOD TO GO!!
While rebuilding my 1972 Chevy C-10, I decided to replace all the brake components rather than fix the old ones. It was not that expensive (around $250 for EVERYTHING from NAPA), saved a lot of time and brakes are not something you want to take chances with. I also changed to DOT 5 to eliminate the hydroscopic DOT 3 issues. The 1972 truck has a power brake dual system with discs up front and drums in the back so it really doesn’t need any upgrades.
The new bits went on fairly easy (although the drum brakes in back with parking brakes were about as complex as drum brakes are going to get – 3 arms would make the job easier) and the problem came with the traditional brake bleeding. Trying to get the brake fluid through all those lines by just pumping the brakes (and yes, I did bleed the master on the bench) was taking forever. I think the residual pressure valve was making the job a pain even with the residual valve button held in with a clamp. An hour of messing with it with marginal results had me looking for a better solution.
I first tried a MityVac and then a NAPA compressor-powered vacuum brake bleeder. But neither were really drawing much through the brake lines (note: rubber brake lines had already been replaced). I thought about just letting a shop do it when I have them build me an exhaust system (I changed to shorty headers on my 230 ci I6). But I really wanted to drive it over there and I hated the thought of a job defeating me.
So with a little web research, I found the Motive Power Bleeder through an eBay store.
This is a very clever device that allows you to fill up its tank with brake fluid, attach the adapter, pump the tank up to pressure, and then simply open the brake slave cylinder valves to let the brake fluid run out with the air bubbles, etc. As old brake fluid comes out, new brake fluid (supplied by the tank) goes in. Other than a bit of pumping, the bleeding and flushing jobs are quick and easily done by one person.
The product and the vendor had a lot of good comments so I thought this is it. I have no problem buying a new useful time-saving tool that is also useable on my other vehicles.
I got the product promptly but it was poorly assembled with a bad tubing clamp and a gauge with a loose face. I added a hose clamp and tried it but I had problems getting pressure built up in the system.
I sent an email about the issue to the factory and was called back within an hour by the owner himself who said that he had to change assemblers. He said he'd ship out a new bleeder. In the mean time, we talked about the system design.
These guys really support their products, are quick to communicate and help, and didn’t pass blame either (something our politicians should take note of). We also talked about the plastic adapter which is being modified into a cast aluminum design that will be much better. But I wasn’t going to wait for the new adapter.
When the new well-assembled bleeder arrived, I was ready to pressure bleed the system. Since you have to pump up the thing by hand (nice when you don’t have a compressor), a leak could be a problem. I could get 10 to 15 PSI with minor leaking, so I figured close enough. I put a bunch of Dot 5 in, pumped up the system and then tried bleeding the front brakes so I could keep an eye on things.
I opened the valve to get goo out on the first wheel when I noticed Dot 5 streaming down on the deck.
I couldn’t get a good enough seal to prevent a fluid leak. So, if you put goo in the bleeder tank, any leak will let fluid out. However, if you only use air pressure and don’t try to have the master cylinder automatically filled from the tank, there is nothing to leak out, and that’s how I moved forward.
I liked the concept, but it wasn’t quite there. If I was going to experiment, I was going to do so with cheaper DOT 3.
If you are a Bolter who doesn’t mind a bit of fabrication, then the answer is to just fix thing so it works like you want it to. If I had constant pressure in the tank, I could see where the adapter was leaking and secure it better. They use a standard 1/4 fitting pressure gauge so I put in an extender plus T fitting between the gauge and the bleeder tank.
Now, I could hook the tank to my compressor, regulated down to 20 PSI (as recommended by the factory GM manual), and find the leaks easily. Anything less that 20 psi didn’t seem to move fluid through the brake system.
I felt that the plastic adapter was deflecting under pressure causing leaks. Well, I can fix that!
I took some 1/8 scrap steel plate and made my own adapter with common plumbing fittings welded on with brass barbed fittings and tubing. I figured 1/8 steel plate wouldn’t deflect very much. But my plate leaked (though, far less than the factory one) and after some head scratching, I figured the problem was that the chains could stretch, allowing the adapter to rock.
A little sitting and thinking overnight and I decided if pressure was applied from the middle with a clamp, rather than at the corners with chains, then it would seal better. Sure enough! A big 5” c clamp fitted it and secured my metal adapter. Now it barely leaks at 20 PSI.
Once the system was fitted and pressurized, it took only a minute to open the bleeder valves, let the air bubble stream out, and then close the bleeder valve. I did one wheel at a time and refilled the master cylinder after each. Bleeding went quickly after that and my brakes work fine now.
The Motive product no doubt works very well on systems that have a screw on cap on the reservoir allowing it to seal up properly, and also with systems that don’t require 20 PSI to get fluid through. I sent pictures and a similar description of problems and solutions to the Company via email and within five minutes, I got a response saying that a number of people also used the C-clamp method -- but some systems still didn’t have room for a clamp, so they still include the chain system. I told them to note that in the instructions to make it easier for the end user. They probably do, but remember, I had one of the older ones bought through a vendor. They also noted that some of the early plastic adapters (mine might be one) were formulated wrong and are sending me another one for free, and a free adapter for my '96 Marquis.
While all this indicates a product that didn’t work so great in this application, once the problems were solved, it worked better than expected. And more importantly, Motive Power is very responsive to their clients. When I get the new plastic adapter, I can try it again with chains and/or clamp and see if it works better, and also see how well it works on a modern vehicle. When I get it to seal completely at 20 PSI, I will try it with fluid in the tank. However, fluid in the tank is not required, and doing one wheel and refilling the master with a single clamp is no work at all compared to the old "DOWN UP DOWN UP DOWN UP” manual process.
Stovebolt Caravan – a/k/a -- a Rolling Road Block