They sent you the right part. What you have originally is a substitute booster from another type of Toyota vehicle. You can see that it overlaps with your clutch master cylinder bolt. The original booster should allow you to remove the clutch MC without touching the booster.
Bench bleeding a master cylinder is necessary despite the existence of opinions that it is not needed.
It can be a somewhat difficult procedure to do correctly as each of the two outlets have to be bled and NO air can be allowed to reenter either side once that side has been bled. No possible entry of air from the bench to the final attachment and tightening of the outlet fittings. The reservoir cannot be allowed so low that air gets into the feed holes at the bottom.This can take great care and needs an effective foolproof method of closing each outlet while the other is bled.
Regardless the controversy; regardless the variety of techniques that can be found for doing it (it's something that each mechanic seems to find his own best way to do) it has to be done and done well or brake issues will never be completely resolved satisfactorily.
But first -- You need to take a break from your truck right now. Frustration never engenders good work.
Honk, yep, I did take a break ...and worked on the electrical. Believe me, I know when frustration sets in, working on critical systems is never a good idea.
So, I did not Bench bleed the MC when it was replaced to answer Eddies question. And quite honestly, I never replaced a master, and not sure how to Bench Bleed a master. Can you help describe it? I would love to do it while replacing the leaking Brake Booster.
They sent you the right part. What you have originally is a substitute booster from another type of Toyota vehicle. You can see that it overlaps with your clutch master cylinder bolt. The original booster should allow you to remove the clutch MC without touching the booster.
What kind of MC do you have? Is it either Aisin or OEM? A Pic will help as well.
When you install the booster, make sure you check the clearance of the front booster rod to the MC. Since your new booster is different from the old booster, the clearance may very well have changed and require adjustment. If you'd like to know how to do this, download the booster installation guide from my site, and look in the Appendix section.
I'm of the opinion that bench bleeding the MC is not necessary. I doubt very much that's the root cause of the problem you are experiencing.
The MC is from Rock Auto, so it's not OEM. I will check your site on how to adjust clearance. I'm interested to see how to adjust a clearance you cannot see after installed. Also the installation guide of the booster. Thanks. Yep on the bench bleeding. You just need to make sure the MC is solid liquid, no bubbles. Attached is a MC shot.
Well, I doubt I could describe the procedure concisely enough to keep your attention but I think that this, of the hundreds available in UTube is short and to the point:
In particular notice that in the second method demonstrated the master cylinder is full and without bubbles at beginning yet during bleeding a considerable amount of air appears visibly within the tubes. Doesn't that clearly demonstrate the error of your premise that "You just need to make sure the MC is solid liquid, no bubbles" ?
Even though the reservoirs may be full, without pre-install bleeding air can be trapped within the chambers of the cylinder itself. For some reason that air is usually very difficult to remove during an on car whole system bleeding procedure and left in place WILL cause a continuing problem.
One thing that the video didn't emphasize enough is that it is CRITICAL that the outlet ports be blocked before releasing pressure on the piston. If they're not fully closed off (by a plug, by your thumbs, by whatever means) the master cylinder will draw air back into the piston chambers on its upstroke making it necessary to start over, to do the bleeding again.
It's like this - you can get lucky and it's not needed, maybe even a couple of times. But sooner or later a job will bite you for not bleeding the M/C in the first place. Most anybody who's earned their living turning wrenches will tell you this and believe me, anyone on the clock or working for themselves doesn't like redoing work at their cost because they tried to cut corners or rely on luck the first time around.
When bench bleeding I have learned one trick from over 35yrs of experience doing mechanical repairs - angle the master slightly up at the front of most of them to orient the intake holes to the bowls slightly down . If you look at how they are built , those intake holes are at the rear of the stroke of the main piston assembly - you want any trapped air in the bore to get out of there and tipping it slightly uphill helps to do that when the piston returns . I also tip the cylinder a bit so the line outputs face somewhat upward - helps remove the air through the output ports . Those simple kits with the plastic adapters and fluid compatible rubber lines are useful for a beginner - I've got a lot of sets of short , bent steel lines and fittings I have made over the years to fit different sizes . Be prepared for a small mess when removing those lines , nothing is wrong and the cylinder doesn't really leak it just drains whatever is in the port outlet . Once installed and the new lines hooked up - that small area will bleed out quickly on the first stroke without going back inside the piston bore .
It would be a very good idea to either buy a factory service manual or at least seek out the electronic copied versions - no other manual has the detail to work on these trucks , especially for someone new .
Honk, Weber Sarge, I replaced the Brake booster today, and while I did not have to, removed the MC and blench bled. Good news there was not a lot of air bubbles, only on the first pump. I actually used some old brake lines to feed the Bowls, just made it easier.
I will be adjusting and bleeding in the next few days. I hate to say it, I may even need to remove the wheel cylinders again to ensure there is no air trapped in them, First things first, adjust and bleed away... Will check my MS and booster clearance.
Racer, thanks, downloaded instructions last week. The PO used 4 spacers to adjust for the incorrect brake booster . Here is the picture of the old and new booster before, and new booster after install. Will post after the adjustments.
Well gents. Here is what was done in a summary (so you don't need to go through the thread):
New Wheel Cylinders where needed (4). Disassembled the new cylinders, filled with fluid and submerged the seal to remove any air trapped)
New rubber brake hoses (5) and all new front steel brake lines
New Brake Booster (the right one, Previous Owner had incorrect one with Washers as spacers) Something tells me he worked hard and could not get brakes to work either.
Adjusted the clearance from booster push rod to master cylinder to 3 CM
All new shoes
New Master cylinder (Bench bled before, and after installation)
Adjusted brakes to the point of no tire rotation, then backed off 2 clicks.
The brakes are non existent. There cannot be any air in the lines... What I noticed with the drums off, when pressing the brake, the shoes (front and rear) do not move until the pedal is roughly half way through travel. I adjusted the push rod to the MC and had no change.
I feel beat, I've been wrenching for a long time and worked on other drum brake cars (Mustangs) without power brakes. Always, always able to resolve. the problem What else can I be missing? There are no leaks and tired of pissing away money without a solution. Any thoughts from all of you (besides selling)?
I am to the point of bringing it to my local yocal garage (he's been around) to see if he can get the binders to fricken bite. This is annoying that I'm unable to fix this. Any other help from all of you is appreciated.
Without reading the whole thread; After adjusting the drums, did you push the pedal down several times then re-adjust. When I had 4 drums on my 70, I found that was the only way I could get good brake pressure. Adjust till locked, jump in truck and push pedal, get out and check them again.
Without reading the whole thread; After adjusting the drums, did you push the pedal down several times then re-adjust. When I had 4 drums on my 70, I found that was the only way I could get good brake pressure. Adjust till locked, jump in truck and push pedal, get out and check them again.
I think that is a valid assumption. I may just finish the replacements, but want to exhaust all possibilities before continuing to dump cash. Even though it's not a bunch, I want to be sure...
Here´s another idea:
Could it be that someone, someday changed work cylinder(s) to one with bigger bore and your stock master cant move enough fluid to fill this(these) big bore(s)?
Is this a typo? Did you mean to say three centimeters?
There is NO clearance adjustment in the brake system that specifies a three centimeter spacing.
I don't remember off the top of my head and my FSM is out in the shop, but the clearance of the booster pushrod to the master cylinder piston needs something less than .020" - (an estimated only number but it reads 20 thousandths of one inch. about the thickness of a thumbnail).
Do you, Boaf, own a copy of the Toyota Factory Service Manual (FSM)?
. Here is the picture of the old and new booster before, and new booster after install. Will post after the adjustments.
