Let’s say that your tank’s tracks were snapped, your gun was broken and you could not fire, your turret was jammed and could not move, your engine had holes in it, or something else.
Would the crew attempt to repair the tank after it was safe, would it be abandoned, would it be taken back to base to be repaired? What type of damages could be repaired by just the crew of any on the battlefield?
How would different things be repaired? Could the crew repair more complex things like engines?
What about holes? Could the crew weld a piece of metal to cover them up or something?
Is the repair process similar between countries? Has is remained the same from World War II to today?
Also, what would the crew do if they did have to leave their tank? Would they be able to go back to base and get a new one eventually?
There were (and still are) essentially three levels of tank repair and maintaince: crew, unit, and depot.
Crew level repairs are fairly simple repairs that can be done without specialized tools or a substantial amount of mechanical training. Fixing a busted track, repainting the vehicle, and the like were usually crew-level repair tasks.
Then you have unit-level repair tasks. These include repairing armor perforations and penetrations, replacing engines and transmissions, and other more complex tasks. These tasks are preformed by the armored unit's organic maintaince and repair units.
For example, in WWII, a U.S. Army tank company (18 tanks) had a maintenance section with a tank recovery vehicle and a small team of mechanics. A tank battalion had a larger maintenance platoon with two tank recovery vehicles, two wrecker trucks, and workshop vehicles.
More complex repairs have to be handled at the depot level. Tasks like repairing serious fire damage, replacing a turret or fitting a larger gun were generally done at the depot level.
Each armored division had an armored maintenance battalion. This battalion had an HQ company and three maintenance companies.
Belton Cooper described some of the work he did while in the maintenance battalion of the 3rd Armored Division in 1944. To be clear: Cooper's book Death Traps isn't a trustworthy source on the development history of U.S. armor in WWII. However, his descriptions of his personal experiences are generally regarded as reliable.
...fire would generate such great heat it would anneal the hardness of the armor plate leaving the tank beyond repair.
If the tank struck a mine, the bottom plate would sometimes be warped to the extent that the hull could not be repaired. In this case, if the turret was not severely damaged, it could be removed and replaced on a good hull.
If the turret was struck in the trunnion mount, jamming the gun elevating mechanism, it could not be repaired but could be removed and replaced with a good turret.
If the tank was penetrated in the ring mount (the junction between the turret and hull), it would warp and damage the ball bearing races on the bottom of the turret and the entire tank would have to be replaced.
One of our maintenance welders found a spent projectile inside a hull. He took a carbon arc and cut the tip off, using this cone to make a plug to weld up the hole the projectile had made. After he ground the surfaces smooth on both sides and we painted the tank inside and outside, it was difficult to find the patch. I always thought this technique was one of the true ironies of warfare, that the projectile also served as the patch.
It took considerable skill on the part of the welder to grind and thus camouflage these patches, because a tank crew did not like to get a replacement tank that had been penetrated, particularly if they felt there had been casualties in the tank. In spite of this, tank crews liked to get their old tank back because of sentimental attachments.
After a reasonably short time, all the damaged vehicles had either been repaired or replaced, and C Company of the Maintenance Battalion headed south to join CCB [(Combat Command B, a brigade-sized tank-infantry-artillery formation)] near Gorron and Mayenne.
There were also other, larger tank repair units at the corps, army, and army group level. These units could perform some very extensive repairs and modifications. For example:
...the 12th Army Group commissioned the building of what became known as Field Expedient Jumbos. These were M4A3 (76) HVSS (often called M4A3E8s or Easy Eights) with additional armor welded to the glacis and turret. These tanks often achieved very near levels of armor to the original Jumbos. The additional armor was scavenged from wrecked tanks. Other M4s and Panthers were preferable. Entire glacis plates from wrecked M4s could be cut out and welded to the new vehicle without needing to move gun travel locks or cutting new apertures for the bow machine-gun. Much of this work was carried out by three civilian factories with an allowance of 85 man hours per vehicle.
All in all, American repair units did an excellent job keeping American tanks in the fight. Cooper again:
The 3rd Armored Division entered combat in Normandy with 232 M4 Sherman tanks. During the [11 month] European Campaign, the Division had some 648 Sherman tanks completely destroyed in combat and we had another 700 knocked out, repaired and put back into operation. This was a loss rate of 580 percent.
It depends on what kind of damage that was done to what part of the tank. Most of the time if it was a mobility kill (hitting the tracks or transmission was out of commission) the tank crew would abandon the tank. In the heat of battle there is no point in trying to repair these parts as it takes too much time and your a sitting duck. To repair the track takes a lot of time and sometimes social equipment which you can’t afford to take out. Especially if there is enemy infantry around who can kill you or ready their anti tank weapons. Transmission fixes you need engineers to fix as well as special equipment to get the thing out and replace it with a new one or fix the old one. After the battle they could come back and try to recover the tank as long as it’s not too damaged.
German tanks for example had a problem with replacing transmissions in most of their tanks. They had to not only remove top part of the tank where the driver and radio man worked, but also remove the components in that area, get a half track with a crane on the back and remove it, then put the new one in and put everything back. This was a process that took 18-24 hours.
If a gun goes out of commission it really depends on the situation. If the main gun is acting up whether a turret jam or something wrong with the breach, they can pull back and let the engineers look at it if they are not too exposed. The crew themselves could also look at it and try to repair it in dire situations. While if the gun itself was destroyed the crew could pull back and get it back to HQ and try to get a replacement. If the main gun goes out the tank isn’t effective anymore so they shouldn’t stay on the field anymore.
Now if a round went straight through the armor of your tank, your having a pretty stressful situation and you need to get out. If the round did hit your ammo storage you might not have time to react. This could cause the rounds to cook off and explode inside the tank. The Sherman, Pz IV, Panther, and many other tanks had this problem. The way the US fixed it was by putting the rounds in water for stowage, this was known as “wet stowage” as the water would smother the rounds if they were hit and prevent a spark. When it happens and your tank is on fire, you have some time to get out and run. You have a pretty good motivator to get out before the tank explodes or burns up. The thing is with many burnt out tanks you see in old pictures is that it has multiple holes in them. The reason for this is because a burnt out tank can not be recovered, while a tank with one or two holes in it and not burned can be. Tanks would put multiple rounds into tanks sometime to prevent them from being recovered. The engineers can recover the tank after the battle, weld and fix any hole or other problems in the tank, then get a new crew in it and send it back out to the field.
It really depends on the situation of the tank. If it’s a mobility kill it can still fight but it can’t move and is a sitting duck to AT weapons and other tanks. Gun or turret problems will take the tank out of the fight, but at least it can try to pull back and try to fix the problem. While critical engine problems aren’t usually fixed by crew or engineers and it’s best to leave if it becomes too dangerous. Honestly the best course of action sometimes is to bail out and hopefully recover the tank later.
Alongside /u/Bacarruda's brilliant answer, I'd personally recommend D-Day to Victory: The Diaries of a British Tank Commander by Sgt Trevor Greenwood. Greenwood commanded a Churchill tank in 9 RTR in France and the Netherlands in 1944/5, and his diaries contain brilliantly vivid descriptions of the results of combat, bailing out of tanks, repair and recovery under fire and the like.